In light of the destructive meteor shower in Russia's Urals region last week, we take a look at the impact of other giant space fragments which hit Earth millions of years ago.

Kara-Kul, Tajikistan: This impact crater lake was formed 25 million years ago, with a diameter of 52 km. Located in the Pamir mountains (also known as the "Roof of the World") of Tajikistan at the borders of China, the bottom of the hole lies 3900 metres below sea level.