12 Trivia Answers That Were Right in School and Are Wrong Now

Here is a question that was on quiz sheets in 2011 and is still on quiz sheets today: what is the world's tallest building?

The answer has not changed. Burj Khalifa, 828 meters, since 2010. But there is a tower going up in Jeddah that has passed 430 meters and is climbing about a floor every five days, and when it stops, the answer changes. Somebody's quiz night in 2029 is going to have a genuinely nasty argument about it.

That is the thing nobody warns you about with trivia. A question is not a fact. A question is a fact plus a date. Most of what you memorized is still fine. A few of them expired quietly while you were not looking, and nobody sent a notice.

Here are twelve that did.

1. How many planets are in the solar system?

Old answer: nine. Current answer: eight.

In August 2006, at a meeting in Prague, the International Astronomical Union adopted a definition of "planet" that requires an object to have cleared the neighborhood around its orbit. Pluto has not. It became a dwarf planet, and a generation of people who had built a mnemonic around it took it personally.

This is the famous one, and it is here mostly because it set the pattern for everything below. Pluto did not change. The definition did. That is true of more entries on this list than you would expect.

2. Which country has the most people?

Old answer: China, for as long as anyone had been counting. Current answer: India, since 2023.

United Nations estimates put India ahead sometime around April 2023, with both countries sitting close to 1.43 billion. The important caveat, which almost no quiz sheet includes, is that the crossover date is an estimate rather than a measurement. Nobody stood at a turnstile. Two enormous populations were modeled forward from their last censuses, and the lines crossed somewhere in there.

So the answer is India, and the date is soft.

3. Which planet has the most moons?

This is the best one on the list, because it has flipped four times in seven years.

For most of the last century the answer was Jupiter, and it was not close. Then in 2019 Saturn edged ahead, 82 to 79. In February 2023 Jupiter took it back. In March 2025 a team led by Edward Ashton had 128 new Saturnian moons recognized in a single announcement, pushing Saturn to 274, more than every other planet in the solar system combined. And in March 2026 the IAU's Minor Planet Center confirmed 11 more around Saturn and 4 more around Jupiter, making it 285 to 101.

Two things worth knowing. First, these are not new moons. They have been there for billions of years. What changed is a technique called shift and stack, where you combine many faint exposures so that a dim moving object rises out of the noise. We are not discovering moons so much as finishing an inventory. Second, the lead researcher's own view is that Jupiter is not catching up.

Write "Saturn" on your answer key. Do not write the number.

4. How tall is Mount Everest?

Old answer: 8,848 meters, or 29,029 feet. Current answer: 8,848.86 meters, or 29,031.7 feet.

The interesting part is why it took until December 2020. Nepal had been using a figure from a 1954 Indian survey. China had argued for a lower number, 8,844.43, because it measured the rock and excluded the snow cap on top. The two countries ran a joint survey and announced a single agreed figure, which settled the number and the snow question at the same time.

A little under a meter, and it took a diplomatic negotiation.

5. What is the heaviest animal that has ever lived?

Blue whale. Then not. Then blue whale again, all inside about seven months.

In August 2023, a paper in Nature described Perucetus colossus, a 39 million year old whale from Peru with absurdly dense bones, and estimated its mass at 85 to 340 tonnes. The top of that range would have beaten any blue whale ever recorded, and the story went everywhere.

In February 2024, a reassessment in PeerJ by Ryosuke Motani and Nicholas Pyenson redid the calculation and landed at 60 to 70 tonnes for a 17 meter animal, or maybe a bit over 110 tonnes if it reached 20 meters. Well short of the largest blue whales at around 270 tonnes. Their argument included a nicely physical point: at the original weights, the thing could not have surfaced to breathe properly.

Blue whale keeps the title. But be honest if you use this one, because it is not settled fact so much as an active argument about method, and further papers have kept refining the numbers since.

6. What is the world's largest aircraft?

Old answer: the Antonov An-225 Mriya. Exactly one was ever built, and it was destroyed at Hostomel Airport outside Kyiv in February 2022.

The current answer depends entirely on what "largest" means, which is the real problem with this question. Stratolaunch's Roc has the widest wingspan of any aircraft ever flown. The An-124 is the largest cargo plane in regular service. The A380 carries the most passengers. The 747-8 is the longest airliner.

This is the entry that bothers me most as a question writer. "Largest" was doing an enormous amount of undefined work even before the An-225 was gone.

7. What is the world's tallest building?

Still Burj Khalifa. Still 828 meters. Correct since 2010, correct today.

It is on the list because it has a visible expiration date. Jeddah Tower sat abandoned at 63 floors for seven years, restarted in January 2025, and passed 430 meters and floor 107 by July 2026. It is designed to clear 1,000 meters, which would make it the first building in history to do so, and the target being reported is August 2028.

Construction targets slip. That one has slipped before. But if you are writing questions for a quiz you plan to reuse, this is an answer with a countdown on it.

8. Where is the hottest place on Earth?

Old answer: El Azizia, Libya, 136 degrees Fahrenheit, recorded in September 1922. That number stood for ninety years.

In September 2012 a World Meteorological Organization panel threw it out. The observer was inexperienced, the instrument was an unsuitable replacement, the surface was not representative of the surrounding area, and the reading did not match anything else in the region.

The record went to Furnace Creek in Death Valley, 134 degrees, July 1913. Which several climatologists also consider shaky, for broadly similar reasons.

So the honest version of this answer is that the record was taken away from one questionable measurement and handed to the next questionable measurement in line. Death Valley is almost certainly the hottest place on Earth. The specific number is another matter.

9. Is Brontosaurus a real dinosaur?

If you were in school between roughly 1970 and 2015, you were taught no. It was a mix-up, the animal is an Apatosaurus, and Brontosaurus was a name that should never have existed.

That came from Elmer Riggs, who concluded in 1903 that the two were the same genus, which meant the older name won. It took until 2015 for anyone to seriously recheck. A study in PeerJ by Emanuel Tschopp, Octavio Mateus and Roger Benson went through diplodocid specimens feature by feature with far more material than Riggs had, and found enough separation to restore Brontosaurus as its own genus.

Not everyone agrees. Some paleontologists still put it back with Apatosaurus. So the correct answer is "probably yes, and it is argued about," which is a dreadful multiple choice option and an excellent thing to say at a dinner table.

10. When did people first reach the Americas?

Old answer: about 13,000 years ago, the Clovis culture, over the Bering land bridge. Clovis first was the textbook consensus for most of the twentieth century.

In 2021, Science published dates for human footprints at White Sands, New Mexico, of roughly 21,000 to 23,000 years ago. That is not a small revision. It puts people in North America during the peak of the last glacial period, when the standard route should have been closed.

The first dating relied on seeds from an aquatic plant, and aquatic plants can take up old carbon and read too old. That was a real objection, not a nitpick. So in 2023 a follow up used two independent methods, radiocarbon on pollen and optically stimulated luminescence on quartz grains, and landed in the same window.

Clovis first had been eroding for decades. White Sands is the clearest single thing that broke it.

11. Which planet is closest to Earth?

Nearly every quiz sheet says Venus. Venus does come closer to Earth than any other planet at its closest approach, so the answer is not wrong exactly.

But almost nobody asking the question means "at closest approach." They mean on average, over time, and by that measure it is Mercury. A 2019 Physics Today piece made the case with a simple simulation: because Mercury hugs the Sun, it spends far more of its orbit on our side of the solar system than Venus does. Averaged across an orbit, Mercury is the closest planet to Earth. By the same logic it is also the closest planet to every other planet, which is one of those facts that sounds like a trick and is not.

This is the odd one out on the list. Nothing changed. The question was ambiguous the entire time and got answered carelessly for a century. Arguably that is worse than being out of date.

12. What is the oldest known art in the world?

A moving target, and moving fast.

In 2019 the record was a hunting scene at Leang Bulu' Sipong 4 in Sulawesi, at least 43,900 years old. In 2021 it went to a painted warty pig at Leang Tedongnge, at least 45,500 years. In July 2024 a new dating method pushed a scene at Leang Karampuang to at least 51,200 years, making it the oldest known figurative art and the oldest known visual storytelling. Then in 2026 Nature reported a hand stencil on a small island off Sulawesi at more than 67,800 years.

Read the category carefully before you put this on a sheet. A hand stencil is not a picture of something. There is also a separate and contested claim for Neanderthal made marks in Spanish caves older than 64,000 years. "Oldest art," "oldest painting," and "oldest picture of an actual thing" are three different questions, and most quiz sheets do not say which one they are asking.

So which of these are actually settled?

Worth sorting honestly, because "this answer changed" and "this answer is currently being fought over" are not the same claim.

Settled. Pluto, Everest's height, the An-225, the El Azizia record, India passing China. These are done. Use them.

Live arguments. The heaviest animal, Brontosaurus, and the oldest art. Real experts currently disagree, and a confident four option question about any of them is a question that punishes people who have read the actual papers.

On a countdown. The tallest building and the moon counts. Correct now, dated soon.

Never a clean question. The closest planet, and the largest aircraft. Both need you to say what you mean before they have an answer at all.

The useful takeaway

An answer key is a snapshot. It ages the same way a photograph does, and mostly you do not notice until someone holds it up next to the present.

This is a slightly uncomfortable thing for anyone who writes questions for a living, and it is a big part of why we rebuild our question pool constantly instead of shipping one bank and walking away. A question about a settled historical fact can sit there for a decade. A question about a record, a count, a tallest, a fastest, or a most needs a review date attached to it. We wrote more about that problem in why trivia gets stale, and about how we split fresh questions from evergreen ones in Daily Challenge versus Trending Now.

If you liked this, the natural companion is ten "facts" everyone gets wrong at trivia night, which covers things that were never true to begin with, and the Mandela Effect, which covers things enormous numbers of people remember happening that never did. Three different flavors of being confidently wrong. If you want to stop being caught by any of them, these habits help more than studying does, and our science and geography sets have the current answers rather than the ones from your fifth grade textbook.

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