Blue whale skeleton at the Central Hall of the Natural History Museum, London, England. 'Hope', nickname of the blue whale skeleton, is 25.2 metres (83 ft) long and is suspended from the ceiling since July 14th 2017. Blue whales are the largest creature ever to have lived in the Earth. In the 1800s there was an estimated amount of 250,000 blue whales across the world's oceans. After decades of commercial hunting the species was to the brink of extinction, with only around 400 surviving in 1966. That year the world took action in London and decided to legally protect blue whales from commercial hunting. Since then the population of blue whales has steadily grown to its current level of around 20,000.