Beyond the answers - interesting background to this quiz

Two rivers, one ancient landscape

The Tigris rises in the mountains of eastern Turkey and runs roughly 1,850 kilometres before joining the Euphrates and emptying into the Persian Gulf. Together the two rivers define Mesopotamia, the "land between the rivers", where some of the world's earliest cities and writing systems emerged. Iraq sits at the heart of that basin, which is why the country appears as the answer here.

A Games with a centennial twist

Atlanta hosted the 1996 Summer Olympics, exactly one hundred years after the first modern Games were held in Athens in 1896. The centennial edition was notable for tight security, a record number of participating nations, and the debut of beach volleyball as a medal sport. It also introduced a mascot that was, by design, unlike anything the Games had seen before.

Twain's most enduring creation

Mark Twain published "The Adventures of Tom Sawyer" in 1876, drawing on his own boyhood in the Mississippi River town of Hannibal, Missouri. The book's sequel, "Adventures of Huckleberry Finn", is often ranked among the greatest American novels. Twain's plain, funny, first-person style helped loosen the grip of formal Victorian prose on American writing.

A noble gas with a bright side

Neon takes its symbol, Ne, from the Greek word "neos", meaning new. It was discovered in 1898 by William Ramsay and Morris Travers, who isolated it from liquefied air. Because neon glows a distinctive orange-red when an electric current passes through it, it became the signature gas of early advertising signs, though most modern "neon" lights actually use other gases.

The album that changed the charts

"Thriller" arrived in 1982 and became the best-selling album in history, with estimated sales above 60 million copies worldwide. Produced with Quincy Jones, it produced seven top-ten singles and pushed Michael Jackson from pop star to global phenomenon. Its title track also gave us one of the most imitated music videos ever made.