Barringer Crater, Arizona, USA, seen from the rim with visitors on the stairs at left. This crater, also known as Meteor Crater, was formed over 50,000 years ago by the impact of an iron meteorite (space rock) colliding with the Earth. The meteorite is thought to have weighed more than 10,000 tonnes. The resulting crater is 183 metres deep, with a diameter of 1200 metres. It is named after the US mining engineer and businessman Daniel Barringer (1860-1929) who first proposed the meteorite impact theory. A visitor centre was built in the 1960s, and the privately owned site was designated a National Natural Landmark in 1967.