Beyond the answers - interesting background to this quiz

A river that crosses more than one border

The Amazon is often described as flowing through a single country, but its basin spreads across several South American nations, including Peru, Colombia and Brazil. The river itself begins in the Peruvian Andes and travels east, with most of its course lying in Brazil. Venezuela, the answer to this quiz question, is one of the countries that shares the wider Amazon Basin, though the main river channel does not pass through it.

Mountains older than the Himalayas

The Western Ghats run along the western edge of India, from Gujarat down to Kerala and Tamil Nadu. They are far older than the Himalayas and are recognised as a UNESCO World Heritage site, partly because of their extraordinary biodiversity. The range also plays a key role in India's monsoon system, catching moisture-laden winds from the Arabian Sea.

The planet that rolls on its side

Most planets spin with only a slight tilt, but Uranus is different: its axis is tilted so far that it effectively rotates on its side. This means its poles take turns facing the Sun during its long orbit. Astronomers believe a massive collision early in its history may explain the unusual tilt.

Where biryani tells a story of trade and empire

Biryani is strongly associated with India, but its history is layered. The dish blends Persian, Mughal and regional Indian cooking traditions, and different cities have their own versions - Hyderabadi, Lucknowi, Kolkata and more. Rice, spices and slow cooking are the constants; the details change from kitchen to kitchen.

Frank Herbert and the desert planet

Frank Herbert is best known for Dune, a science fiction novel set on a harsh desert world where water is precious and politics is ruthless. Published in the 1960s, it became one of the best-selling science fiction novels ever written and influenced generations of writers, filmmakers and game designers.