{
  "version": 2,
  "note": "Curated, fact-checked crumbs across many domains — not tied to any field. tags drive topic relevance; quiz is the optional ask-first form.",
  "crumbs": [
    {
      "id": "first-bug-moth",
      "tags": ["coding", "history"],
      "text": "The first computer 'bug' was a literal one: in 1947 a moth was found jamming a relay in the Harvard Mark II. Grace Hopper's team taped it into the logbook as 'the first actual case of bug being found.'",
      "quiz": {
        "q": "What was taped into a 1947 logbook as 'the first actual case of bug being found'?",
        "a": "A real moth, pulled out of a relay in the Harvard Mark II computer."
      }
    },
    {
      "id": "ada-first-algorithm",
      "tags": ["coding", "history"],
      "text": "The first published computer algorithm predates computers by a century. In 1843 Ada Lovelace wrote a method for Babbage's never-built Analytical Engine to compute Bernoulli numbers — widely considered the first program.",
      "quiz": {
        "q": "Who wrote what's considered the first computer algorithm, and roughly when?",
        "a": "Ada Lovelace, in 1843, for Babbage's Analytical Engine."
      }
    },
    {
      "id": "python-monty",
      "tags": ["coding"],
      "text": "Python isn't named after the snake. Guido van Rossum named it after Monty Python's Flying Circus — which is why the docs have always leaned toward spam, silliness, and absurd examples.",
      "quiz": {
        "q": "Where does the programming language Python get its name?",
        "a": "From the comedy troupe Monty Python, not the snake."
      }
    },
    {
      "id": "git-few-days",
      "tags": ["coding", "history"],
      "text": "Git was written by Linus Torvalds in a matter of days in 2005, after the tool Linux had been using pulled its free license. He self-deprecatingly named it after 'an unpleasant person.'",
      "quiz": {
        "q": "How long did Linus Torvalds take to build the first working version of Git?",
        "a": "Just a few days, in April 2005."
      }
    },
    {
      "id": "at-sign-email",
      "tags": ["coding", "history"],
      "text": "Ray Tomlinson picked '@' for email addresses in 1971 for a practical reason: it meant 'at,' and it was one of the few symbols that would never appear in someone's name, so it cleanly split user from host.",
      "quiz": {
        "q": "Why did the '@' symbol get chosen for email addresses?",
        "a": "It meant 'at' and never appeared in names, so it safely separated the user from the host."
      }
    },
    {
      "id": "teapot-418",
      "tags": ["coding"],
      "text": "HTTP status 418 'I'm a teapot' is a real registered code, from a 1998 April Fools' spec for brewing coffee. It survives as an in-joke — some servers still return it, and clients still handle it.",
      "quiz": {
        "q": "What does HTTP status code 418 officially mean?",
        "a": "'I'm a teapot' — a joke code from a 1998 April Fools' RFC that stuck around."
      }
    },
    {
      "id": "lightning-hotter-sun",
      "tags": ["science"],
      "text": "A lightning bolt heats the air around it to roughly 30,000 K — about five times hotter than the surface of the Sun. That sudden expansion of superheated air is the thunder you hear.",
      "quiz": {
        "q": "How does a lightning bolt's temperature compare to the Sun's surface?",
        "a": "About five times hotter — ~30,000 K versus the Sun's surface at ~5,800 K."
      }
    },
    {
      "id": "water-freeze-expand",
      "tags": ["science"],
      "text": "Water is unusual: it expands about 9% when it freezes. That one property bursts pipes, splits rock into soil, and floats ice on top of ponds instead of sinking it.",
      "quiz": {
        "q": "What unusual thing does water do when it freezes, unlike most liquids?",
        "a": "It expands (~9%) and becomes less dense, so ice floats."
      }
    },
    {
      "id": "glass-not-liquid",
      "tags": ["science", "history"],
      "text": "Glass is an amorphous solid, not a slow-moving liquid. Old cathedral windows are thicker at the bottom because of how they were made, not because the glass 'flowed' down over centuries.",
      "quiz": {
        "q": "Do old windows get thicker at the bottom because glass slowly flows downward?",
        "a": "No — glass is a solid; the uneven thickness comes from the old manufacturing process."
      }
    },
    {
      "id": "helium-finite",
      "tags": ["science"],
      "text": "Helium is genuinely running out. It's so light that once released it drifts up and escapes Earth's gravity into space for good — the party balloon is venting a finite resource we mostly pull from natural gas.",
      "quiz": {
        "q": "Why is helium considered a non-renewable resource on Earth?",
        "a": "It's light enough to escape Earth's gravity into space once released, and can't be practically recaptured."
      }
    },
    {
      "id": "neutron-star-teaspoon",
      "tags": ["space", "science"],
      "text": "A neutron star is so dense that a single teaspoon of its material would weigh about a billion tonnes on Earth — roughly the mass of a mountain packed into a spoon.",
      "quiz": {
        "q": "Roughly how much would one teaspoon of neutron-star material weigh on Earth?",
        "a": "About a billion tonnes — comparable to a mountain."
      }
    },
    {
      "id": "saturn-floats",
      "tags": ["space", "science"],
      "text": "Saturn is less dense than water. If you had a bathtub big enough, the whole planet would float — its average density is about 0.7 g/cm³, below water's 1.0.",
      "quiz": {
        "q": "Which planet in our solar system would float in water, given a big enough tub?",
        "a": "Saturn — its average density is less than water's."
      }
    },
    {
      "id": "sun-light-8min",
      "tags": ["space", "science"],
      "text": "Sunlight takes about 8 minutes 20 seconds to reach Earth. You never see the Sun as it is now — always as it was over eight minutes ago.",
      "quiz": {
        "q": "How long does light from the Sun take to reach Earth?",
        "a": "About 8 minutes and 20 seconds."
      }
    },
    {
      "id": "venus-day",
      "tags": ["space"],
      "text": "A day on Venus is longer than its year. Venus turns so slowly that one rotation takes 243 Earth days, while a full orbit of the Sun takes only 225.",
      "quiz": {
        "q": "On which planet is a single day longer than its entire year?",
        "a": "Venus — 243 Earth days to rotate once, 225 to orbit the Sun."
      }
    },
    {
      "id": "stars-vs-sand",
      "tags": ["space"],
      "text": "There are more stars in the observable universe than grains of sand on all of Earth's beaches and deserts combined — very roughly 10²² stars versus about 10¹⁹ grains of sand.",
      "quiz": {
        "q": "Which is greater: stars in the observable universe, or grains of sand on Earth?",
        "a": "Stars — by a factor of roughly a thousand."
      }
    },
    {
      "id": "earth-day-lengthening",
      "tags": ["space", "science"],
      "text": "Earth's day is slowly getting longer. The Moon's tidal pull drags on our spin, adding about 1.7 milliseconds to the length of a day every century — which is why leap seconds exist.",
      "quiz": {
        "q": "Why is the length of Earth's day very slowly increasing?",
        "a": "The Moon's tidal pull is gradually slowing Earth's rotation (~1.7 ms per century)."
      }
    },
    {
      "id": "octopus-three-hearts",
      "tags": ["nature", "science"],
      "text": "An octopus has three hearts and blue blood. Two hearts pump to the gills and one to the body; the blood is blue because it carries oxygen on copper, not iron.",
      "quiz": {
        "q": "How many hearts does an octopus have, and why is its blood blue?",
        "a": "Three hearts; the blood is blue because it uses copper (hemocyanin) instead of iron to carry oxygen."
      }
    },
    {
      "id": "banana-berry",
      "tags": ["nature", "food"],
      "text": "Botanically, a banana is a berry — but a strawberry is not. 'Berry' has a strict botanical definition about how the fruit forms, and everyday names don't follow it.",
      "quiz": {
        "q": "Which is botanically a berry: a banana or a strawberry?",
        "a": "The banana — a strawberry is not a true berry."
      }
    },
    {
      "id": "sharks-older-trees",
      "tags": ["nature", "history"],
      "text": "Sharks are older than trees. Sharks have swum the oceans for around 450 million years; the first trees appeared roughly 350–390 million years ago.",
      "quiz": {
        "q": "Which came first: sharks or trees?",
        "a": "Sharks — by tens of millions of years."
      }
    },
    {
      "id": "wombat-cube-poop",
      "tags": ["nature"],
      "text": "Wombats produce cube-shaped droppings — the only known animal to make cubes. Their intestines have varying elasticity that molds the flat sides, so the pellets don't roll away and can mark territory.",
      "quiz": {
        "q": "Which animal is famous for producing cube-shaped droppings?",
        "a": "The wombat."
      }
    },
    {
      "id": "tardigrade-space",
      "tags": ["nature", "science"],
      "text": "Tardigrades — microscopic 'water bears' — have survived the raw vacuum and radiation of open space. They dry into a near-dead state and revive when conditions improve.",
      "quiz": {
        "q": "Which tiny animal has been shown to survive the vacuum of open space?",
        "a": "The tardigrade (water bear)."
      }
    },
    {
      "id": "flamingo-flamboyance",
      "tags": ["nature", "language"],
      "text": "A group of flamingos is called a 'flamboyance.' Their pink color isn't built in either — it comes from pigments in the algae and shrimp they eat.",
      "quiz": {
        "q": "What is the collective noun for a group of flamingos?",
        "a": "A flamboyance."
      }
    },
    {
      "id": "oxford-older-aztec",
      "tags": ["history"],
      "text": "Oxford University is older than the Aztec Empire. Teaching at Oxford dates to around 1096; the Aztec capital Tenochtitlan wasn't founded until 1325.",
      "quiz": {
        "q": "Which is older: Oxford University or the Aztec Empire?",
        "a": "Oxford — teaching there began (~1096) over two centuries before Tenochtitlan was founded (1325)."
      }
    },
    {
      "id": "cleopatra-timeline",
      "tags": ["history"],
      "text": "Cleopatra lived closer in time to the Moon landing than to the building of the Great Pyramid. The Pyramid was already ~2,500 years old in her day; the Moon landing was only ~2,000 years after it.",
      "quiz": {
        "q": "Was Cleopatra closer in time to the Great Pyramid's construction or to the Moon landing?",
        "a": "The Moon landing — the Pyramid was ~2,500 years before her, the landing ~2,000 years after."
      }
    },
    {
      "id": "great-wall-space",
      "tags": ["history", "space"],
      "text": "The Great Wall of China is not visible from space with the naked eye — it's long but only a few meters wide, and blends into the terrain. The claim spread for decades before astronauts debunked it.",
      "quiz": {
        "q": "Can you see the Great Wall of China from space with the naked eye?",
        "a": "No — it's too narrow and blends into the landscape, despite the popular myth."
      }
    },
    {
      "id": "napoleon-height",
      "tags": ["history"],
      "text": "Napoleon wasn't short. At about 1.68 m he was average for a Frenchman of his era; the 'tiny Napoleon' image came from British propaganda and a mix-up between French and English inches.",
      "quiz": {
        "q": "Was Napoleon unusually short for his time?",
        "a": "No — he was about average height; the myth came from propaganda and an inch-unit mix-up."
      }
    },
    {
      "id": "bubble-wrap-wallpaper",
      "tags": ["history"],
      "text": "Bubble wrap was invented in 1957 as textured wallpaper. It failed at that, briefly tried being greenhouse insulation, and only found its calling once someone thought to wrap fragile things in it.",
      "quiz": {
        "q": "What was bubble wrap originally invented to be?",
        "a": "Textured wallpaper."
      }
    },
    {
      "id": "russia-timezones",
      "tags": ["geography"],
      "text": "Russia spans 11 time zones — when it's morning on its western edge, it's already evening in the east. It's so wide that two of its cities are farther apart than New York and London.",
      "quiz": {
        "q": "How many time zones does Russia span?",
        "a": "Eleven."
      }
    },
    {
      "id": "africa-hemispheres",
      "tags": ["geography"],
      "text": "Africa is the only continent that sits in all four hemispheres — northern, southern, eastern, and western — because both the equator and the prime meridian pass through it.",
      "quiz": {
        "q": "Which continent lies in all four hemispheres at once?",
        "a": "Africa — crossed by both the equator and the prime meridian."
      }
    },
    {
      "id": "canada-lakes",
      "tags": ["geography"],
      "text": "Canada has more lakes than the rest of the world combined — well over half of all the lakes on Earth lie within its borders.",
      "quiz": {
        "q": "Which country contains more lakes than the rest of the world put together?",
        "a": "Canada."
      }
    },
    {
      "id": "everest-mauna-kea",
      "tags": ["geography", "science"],
      "text": "Everest is the highest point above sea level, but not the tallest mountain. Measured from its base on the ocean floor, Hawaii's Mauna Kea is over 10,000 m tall — taller than Everest.",
      "quiz": {
        "q": "Measured base to peak, which mountain is taller than Everest?",
        "a": "Mauna Kea — its base sits on the ocean floor, giving it over 10,000 m of total height."
      }
    },
    {
      "id": "run-definitions",
      "tags": ["language"],
      "text": "The word with the most definitions in English is 'run' — the Oxford English Dictionary lists over 600 senses for it, from a river running to running a business to a run in your sock.",
      "quiz": {
        "q": "Which English word has the most definitions in the Oxford English Dictionary?",
        "a": "'Run', with over 600 distinct senses."
      }
    },
    {
      "id": "tittle",
      "tags": ["language"],
      "text": "The little dot over a lowercase 'i' or 'j' has a name: it's called a 'tittle.' The word survives today mainly in the phrase 'to a T' (originally 'to a tittle').",
      "quiz": {
        "q": "What is the name for the dot over a lowercase 'i' or 'j'?",
        "a": "A tittle."
      }
    },
    {
      "id": "greenland-naming",
      "tags": ["language", "history", "geography"],
      "text": "Greenland is icy and Iceland is green — because Erik the Red named the icy island 'Greenland' on purpose, as a marketing trick to lure settlers there.",
      "quiz": {
        "q": "Why is icy Greenland named 'green'?",
        "a": "Erik the Red gave it an appealing name to attract settlers."
      }
    },
    {
      "id": "birthday-paradox",
      "tags": ["math"],
      "text": "In a room of just 23 people, it's more likely than not that two share a birthday. It feels wrong because you're comparing every pair, not matching one specific date — there are 253 possible pairs.",
      "quiz": {
        "q": "How few people need to be in a room for a >50% chance that two share a birthday?",
        "a": "Just 23."
      }
    },
    {
      "id": "googol-atoms",
      "tags": ["math", "space"],
      "text": "A googol — a 1 followed by 100 zeros — is larger than the number of atoms in the entire observable universe, which is estimated at only about 10⁸⁰.",
      "quiz": {
        "q": "Which is bigger: a googol, or the number of atoms in the observable universe?",
        "a": "A googol (10¹⁰⁰) — about 10²⁰ times more than the ~10⁸⁰ atoms."
      }
    },
    {
      "id": "zero-late",
      "tags": ["math", "history"],
      "text": "Zero as a number is a surprisingly late invention. The Romans had no symbol for it, and the idea of zero as a value you can calculate with reached Europe only around the 12th century.",
      "quiz": {
        "q": "Did the ancient Romans have a symbol for zero?",
        "a": "No — zero as a usable number reached Europe much later, around the 12th century."
      }
    },
    {
      "id": "mona-lisa-eyebrows",
      "tags": ["art", "history"],
      "text": "The Mona Lisa has no visible eyebrows or eyelashes. Whether Leonardo left them out, they faded, or an early cleaning removed them is still debated.",
      "quiz": {
        "q": "What famous facial feature is missing from the Mona Lisa?",
        "a": "Her eyebrows (and eyelashes) — they're not visible in the painting."
      }
    },
    {
      "id": "happy-birthday-copyright",
      "tags": ["art", "history"],
      "text": "'Happy Birthday to You' was under copyright until 2016. For decades, films and restaurants dodged royalties by singing something else — until a court finally ruled the song public domain.",
      "quiz": {
        "q": "Until what year was 'Happy Birthday to You' claimed to be under copyright?",
        "a": "2016, when a court ruled it public domain."
      }
    },
    {
      "id": "carrots-purple",
      "tags": ["food", "history"],
      "text": "Carrots were originally purple, white, and yellow — not orange. The familiar orange carrot was cultivated later, popularized by Dutch growers around the 17th century.",
      "quiz": {
        "q": "What color were carrots before the familiar orange ones were bred?",
        "a": "Mostly purple, white, and yellow."
      }
    },
    {
      "id": "peanuts-legumes",
      "tags": ["food", "nature"],
      "text": "Peanuts aren't nuts. They're legumes — closer kin to peas and lentils — and, unlike tree nuts, they grow underground.",
      "quiz": {
        "q": "Botanically, what family do peanuts actually belong to?",
        "a": "Legumes (like peas and beans), not tree nuts."
      }
    },
    {
      "id": "ketchup-medicine",
      "tags": ["food", "history"],
      "text": "In the 1830s, ketchup was sold as medicine. An Ohio doctor marketed tomato-based pills as a cure for indigestion and other ailments before it settled into being a condiment.",
      "quiz": {
        "q": "In the 1830s, ketchup was briefly sold as what?",
        "a": "Medicine — tomato pills marketed as a cure for indigestion."
      }
    },
    {
      "id": "stomach-lining",
      "tags": ["body", "science"],
      "text": "Your stomach essentially rebuilds itself every few days. The acid inside is strong enough to digest the stomach itself, so its lining is replaced constantly to stay ahead of the damage.",
      "quiz": {
        "q": "Why does the stomach replace its own lining every few days?",
        "a": "Its acid is strong enough to digest the stomach itself, so the lining must constantly renew."
      }
    },
    {
      "id": "taller-morning",
      "tags": ["body"],
      "text": "You're about a centimeter taller in the morning than at night. Through the day, gravity gently compresses the soft discs between your vertebrae; lying down overnight lets them spring back.",
      "quiz": {
        "q": "Why are you slightly taller in the morning than at night?",
        "a": "The discs in your spine compress under gravity during the day and re-expand while you lie down."
      }
    },
    {
      "id": "brain-energy",
      "tags": ["body", "science"],
      "text": "Your brain is about 2% of your body weight but burns roughly 20% of your energy — even at rest. Thinking is one of the most expensive things your body does.",
      "quiz": {
        "q": "Roughly what share of your body's energy does the brain use, despite its small size?",
        "a": "About 20%, while being only ~2% of body weight."
      }
    },
    {
      "id": "honey-never-spoils",
      "tags": ["food", "history", "science"],
      "text": "Honey doesn't spoil. Its low water content and natural acidity make it a place bacteria can't grow — archaeologists have found 3,000-year-old honey in Egyptian tombs still edible.",
      "quiz": {
        "q": "Why can honey stay edible for thousands of years?",
        "a": "Very low water content plus acidity stop bacteria and fungi from growing in it."
      }
    }
  ]
}