Beyond the answers - interesting background to this quiz

The river that became a national anthem

Bedrich Smetana's "The Moldau" is part of a cycle called "Ma Vlast," or "My Fatherland," completed in the 1870s. The piece follows the Vltava River from its humble beginnings as two small springs, through a hunt in the woods, a peasant wedding and moonlight on the water, before it flows past Prague. Smetana, who was deaf by the time he finished the cycle, never heard the full work performed. It remains a powerful symbol of Czech identity.

Where the world's water actually goes

Fresh water makes up only a small fraction of Earth's total water supply, which is why the answer lands below 3 percent. Most of the planet's water is salt water in the oceans. Of the fresh water that exists, much is locked in glaciers and ice caps, and a significant share sits underground as groundwater. The water in rivers and lakes, the part we most easily picture, is a tiny slice of the whole.

A wall that divided a city and a world

The Berlin Wall came down in 1989, near the end of the 20th century. Built in 1961, it split East and West Berlin for 28 years, becoming the most visible symbol of the Cold War divide between the Soviet bloc and the West. When the barriers opened, crowds crossed freely and pieces of the wall were chipped away by citizens and eventually sold around the world as relics of a divided era.

The quiet revolution of the euro

Italy and Austria are two of the countries that replaced their national currencies with the euro. Italy said goodbye to the lira, a currency with roots stretching back centuries, while Austria traded in the schilling. Euro coins and notes entered circulation in 2002, though the currency existed on paper from 1999. For travellers, the shift ended the ritual of changing money at every border crossing within the eurozone.