01Science

Everest is the highest mountain, but Mauna Kea is the tallest

Height and tallness are measured from different places. Everest's summit sits about 8,849 metres above sea level, higher than anything else on Earth. Mauna Kea in Hawaii rises only about 4,200 metres above the water, but its base is on the Pacific seafloor, so from foot to summit it is around 10,000 metres. A third answer exists: because Earth bulges at the equator, Ecuador's Chimborazo summit is the point furthest from the planet's centre.

Most "biggest" and "tallest" quiz answers depend entirely on where the measurement starts.

02Sport

The marathon's odd 26.2 miles comes from one Olympic course in London

The name comes from the Greek legend of a runner carrying news from Marathon to Athens, but not the distance. Early marathons ran roughly 25 miles and varied by event. For the 1908 London Games the course was laid out from Windsor Castle to the stadium at White City, coming to 26 miles 385 yards. Athletics authorities fixed that figure as the standard distance in 1921, and it has stuck ever since.

Explains why the number looks arbitrary: it is a one-off course length that got frozen into a world standard.

03Science

Hydrogen is most abundant in the universe, oxygen in the rock under you

Ordinary matter across the universe is roughly three quarters hydrogen by mass, the simplest atom, one proton. But Earth's crust is about 46 percent oxygen by mass, because oxygen is locked into the silicate minerals that make up most rock. The air is a third answer: 78 percent nitrogen by volume. So the correct reply depends entirely on where the question means.

Turns a question you can get wrong three ways into one you can reason out.

04World

The Nile or the Amazon is longest, depending on where you say a river begins

Reference books usually give the Nile about 6,650 km and the Amazon about 6,400 km, and that is the answer most quizzes want. The gap is small enough that definitions decide it. The Amazon has several candidate source streams high in the Peruvian Andes, and its mouth spreads into a huge estuary with no obvious cut-off point. Pick the far source and a distant mouth and the Amazon wins. Geographers genuinely disagree.

Shows that the biggest facts in geography often rest on a measuring convention rather than a measurement.

05Money

The oldest company answer, Kongō Gumi, stopped being independent in 2006

Kongō Gumi was founded in 578 in Osaka to build the Shitennō-ji Buddhist temple, and stayed in the same family for dozens of generations. Debt forced it to be absorbed in 2006, so it now trades as a subsidiary of another construction firm rather than on its own. Quizzes wanting a continuously independent business often accept Stora Enso, the Finnish-Swedish paper and packaging group, which traces its origins to shares in a Swedish copper mine recorded in 1288.

Superlatives about age depend on whether a business surviving inside a bigger owner still counts as itself.

06Culture

The tallest building counts spires but not antennas, which decides titles

Burj Khalifa in Dubai, 828 metres, has held the record since 2010. The rule that matters comes from the Council on Tall Buildings and Urban Habitat: height runs from pavement to the architectural top, so a decorative spire counts and a broadcast antenna bolted on afterwards does not. That is how Kuala Lumpur's Petronas Towers took the title from Chicago's Sears Tower in 1998 despite having fewer floors and a lower roof.

Every tallest-building argument is really an argument about where the building is agreed to stop.

07Ideas

The economics Nobel is not Nobel's; a central bank created it in 1968

Alfred Nobel's will funded five prizes: physics, chemistry, physiology or medicine, literature, and peace. Economics is not among them. Sweden's central bank, the Sveriges Riksbank, endowed a separate award in economic sciences in memory of Nobel in 1968, first given the following year. It is announced alongside the others and handed out at the same Stockholm ceremony, which is why almost everyone calls it a Nobel. Some of Nobel's descendants have objected to that.

Lets you answer both versions of the question: five original prizes, six awards announced each year.

07

That's the set.

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