Beyond the answers - interesting background to this quiz

A wall that fell in one night

The Berlin Wall had divided the city since 1961, but on the evening of 9 November 1989, crowds gathered at the border crossings after an East German official's confusing press conference suggested travel restrictions were being lifted. Overwhelmed guards eventually opened the barriers, and Berliners spent the night celebrating on both sides of the wall. Within a year, Germany had moved toward reunification.

The river that feeds six countries

The Mekong begins on the Tibetan Plateau and runs through China, Myanmar, Laos, Thailand, Cambodia and Vietnam before emptying into the South China Sea. It supports some of the world's largest inland fisheries, and its seasonal floods are essential to farming along its banks. Dams built upstream in recent decades have changed the river's flow, raising concerns for the millions of people who depend on it.

The composer who mapped the sky

Gustav Holst completed "The Planets" between 1914 and 1916, writing a separate movement for seven planets known at the time, each with its own character: Mars the bringer of war, Venus the bringer of peace, Jupiter the bringer of jollity. Holst was interested in astrology rather than astronomy, so the suite reflects the planets as symbols rather than scientific facts. Earth was not included, and Pluto had not yet been discovered.

Why Mars has such dramatic seasons

Like Earth, Mars is tilted on its axis, which gives it seasons. But its orbit is far more elliptical than ours, so the distance between Mars and the Sun varies considerably over a Martian year. That makes some seasons much more extreme than others, with huge swings in temperature and dust storms that can envelop the entire planet.

A capital with a long history

Amman has been inhabited for thousands of years and was known in antiquity as Philadelphia, one of the cities of the Decapolis. Its Roman theatre, cut into a hillside, still stands in the middle of the modern city. Today Amman is one of the oldest continuously inhabited capitals in the world, blending ancient ruins with a busy contemporary urban centre.