Eerie photos show the Great Smog of London in 1952, which killed 12,000 people and changed the way the world saw air pollution

• In 1952, London was blanketed under a dark cloud of human-made air pollution known as the Great Smog.
• The smog killed about 12,000 people, along with a dozen cattle who choked on the poisonous air.
• The UK later enacted the Clean Air Act in 1956, banning coal in homes and in many factories in populated areas.

Over the course of five days in 1952, the city of London was blanketed in a thick layer of poisonous air that would result in the deaths of thousands.

The Great Smog of 1952 killed 12,000 people. At the time, people didn't realize how toxic the air was because they were used to the smog.