Beyond the answers - interesting background to this quiz

The empire that dissolved on live television

The Soviet Union formally ceased to exist in December 1991, when the red flag was lowered over the Kremlin for the last time. What had been built over seven decades unravelled in a matter of months, driven by economic stagnation, nationalist movements in the republics and the policies of glasnost and perestroika. Fifteen independent states emerged from the collapse, and the event reshaped global politics almost overnight.

The oldest number puzzle in mathematics

Prime numbers, divisible only by one and themselves, have fascinated thinkers since antiquity. Euclid proved over two thousand years ago that there is no largest prime, a result that still underpins modern number theory. Today they guard your bank details: the RSA encryption used across the internet relies on the difficulty of factoring very large numbers into their prime building blocks.

A sea between two worlds

The Andaman Sea lies in Southeast Asia, bordered by Myanmar, Thailand, Indonesia and the Indian territory of the Andaman and Nicobar Islands. It connects to the Bay of Bengal and the Strait of Malacca, one of the world's busiest shipping lanes. Its warm, shallow waters hold coral reefs and dive sites such as the Similan Islands, making it a magnet for marine tourism.

The accidental discovery that changed medicine

Wilhelm Röntgen spotted the strange glow of X-rays in 1895 while experimenting with cathode rays in a darkened laboratory. He named them "X" because their nature was unknown at the time, and his first published image showed the bones of his wife's hand. The discovery earned him the very first Nobel Prize in Physics in 1901 and quickly transformed diagnosis and surgery.

Zeus and the generation before Olympus

In Greek myth, Zeus was the son of the Titans Cronus and Rhea, part of the generation that ruled before the Olympian gods. Cronus, warned that one of his children would overthrow him, swallowed each newborn, until Rhea hid Zeus and tricked him with a wrapped stone. The eventual war between the Titans and the Olympians, known as the Titanomachy, ended with Zeus taking control of the sky.