Beyond the answers - interesting background to this quiz

One border, two very different neighbours

China shares a border with both Nepal and Mongolia, which is why it is the answer here. Nepal sits to its south-west, tucked against the Himalayas, while Mongolia stretches along its northern edge. Between them, China borders more countries than almost any other nation on Earth.

The element that glows without being asked

Polonium is radioactive, discovered by Marie and Pierre Curie in 1898 and named after Marie's homeland, Poland. It occurs naturally in uranium ores but only in tiny traces, so it is usually produced artificially in reactors. Lead and mercury, by contrast, are toxic heavy metals but not radioactive in the way polonium is.

A language family stretched across a continent

Polish belongs to the Slavic branch of the Indo-European language family, alongside Russian, Czech, Ukrainian and others. Norwegian is a Germanic language, and Spanish is a Romance language descended from Latin. The Slavic languages share deep roots in vocabulary and grammar, which is why speakers of one can often recognise fragments of another.

The first footprints on another world

Apollo 11 landed on the Moon in July 1969, and Neil Armstrong became the first person to step onto its surface. The mission was watched live by an estimated 600 million people, a record audience at the time. The Moon remains the only celestial body humans have visited in person.

An invention with a disputed credit line

Alexander Graham Bell patented the telephone in 1876, and the patent is the reason he is usually named as its inventor. Yet several others, including Elisha Gray and Antonio Meucci, worked on similar devices around the same period. Bell's patent became one of the most valuable in history and shaped how the world would communicate.