Beyond the answers - interesting background to this quiz

A speech that changed the course of a movement

Martin Luther King Jr. delivered "I Have a Dream" in 1963 from the steps of the Lincoln Memorial in Washington, D.C., during the March on Washington for Jobs and Freedom. The event drew a crowd of more than 200,000 people, and the speech became one of the defining moments of the American civil rights movement. King drew on the language of the Declaration of Independence and the Bible, and the line about his "four little children" was partly improvised after the gospel singer Mahalia Jackson called out for him to tell the crowd about the dream.

The slow turning of a planet

Earth rotates from west to east, which is why the sun appears to rise in the east and set in the west. A full rotation takes roughly 24 hours, giving us day and night, and the planet's tilt on its axis is what produces the seasons. Because of the direction of rotation, weather systems in the Northern Hemisphere tend to swirl counterclockwise, while those in the Southern Hemisphere spin clockwise.

The tallest trees on Earth

The giant sequoia, native to the western slopes of California's Sierra Nevada, is the largest tree species in the world by volume. These trees can live for thousands of years and their massive trunks make them heavier and bulkier than any other species. They are not, however, the tallest - that title belongs to the coast redwood, a close relative that can stretch higher than 100 metres.

A capital at the crossroads of history

Amman has been inhabited for thousands of years, with evidence of settlement stretching back to the Bronze Age. In ancient times it was known as Philadelphia, one of the cities of the Decapolis, a group of Hellenistic cities in the region. Today it is the capital of Jordan and one of the largest cities in the Levant, known for its Roman theatre and citadel hill.

Belfast and the story of a divided island

Belfast is the capital of Northern Ireland and the second-largest city on the island of Ireland after Dublin. The city grew rapidly during the Industrial Revolution, becoming famous for linen, rope-making and shipbuilding - the Titanic was built in its shipyards. Northern Ireland was created in 1921 when Ireland was partitioned, and Belfast became its capital, a status it still holds today.