Beyond the answers - interesting background to this quiz

The organ you can never take off

Skin is the body's largest organ, and it is also the one most people forget to count. It covers roughly two square metres in an average adult and accounts for around 15 per cent of body weight. Skin does far more than wrap us up: it helps regulate temperature, blocks microbes and synthesises vitamin D when sunlight hits it. It also renews itself constantly, shedding millions of cells every day.

Waterloo, the battle that closed a chapter

Napoleon's defeat at Waterloo in 1815 ended more than two decades of warfare that had reshaped Europe. The battle was fought near the village of Waterloo, south of Brussels, in present-day Belgium, against the armies of the Duke of Wellington and Gebhard Leberecht von Blücher. Napoleon was exiled to Saint Helena, a remote island in the South Atlantic, where he died in 1821. The phrase "to meet one's Waterloo" still means facing a decisive defeat.

The Andes and the Danube: two record-holders

The Andes form the world's longest continental mountain range, stretching roughly 7,000 kilometres along South America's western edge. The Danube is Europe's second-longest river, and it passes through or borders ten countries, including Austria, before emptying into the Black Sea. Both feature in this quiz as reminders that geography often rewards the extremes.

The Moon landing in context

Neil Armstrong stepped onto the lunar surface in 1969, at the climax of NASA's Apollo programme. An estimated 600 million people watched the broadcast worldwide, making it one of the most shared moments in television history. Armstrong's words about "one small step" were heard live, though the exact phrasing he intended has been debated ever since.