Beyond the answers - interesting background to this quiz

The book that gave us Big Brother

Winston Smith, the weary protagonist of George Orwell's 1984, has outlived his own author by decades. Orwell wrote the novel largely in the late 1940s, drawing on his observations of totalitarian regimes and wartime propaganda. Terms from the book - Big Brother, doublethink, the memory hole - slipped into everyday English and are still used whenever surveillance or manipulated language is debated. Published in 1949, the novel has never been out of print.

The river that drains a continent

The Amazon carries more water than any other river on Earth, and its basin covers a huge share of South America. The river rises in the Peruvian Andes and crosses Brazil before emptying into the Atlantic. Its flood pulses are so powerful that they influence the climate far beyond the rainforest, and the plume of fresh water it releases can be detected in the ocean well away from the coast.

A border drawn by mountains and sea

The Mediterranean has shaped the map of Europe in ways that still matter. Poland sits far to the north-east, on the Baltic Sea, so it has no Mediterranean coastline at all - unlike Italy and France. The Atlas Mountains, meanwhile, run across Morocco, Algeria and Tunisia, separating a relatively fertile northern strip from the Sahara to the south. For travellers, the range offers snow in winter and trekking within a day's drive of Marrakech.