A massive bucket wheel excavator at an open cast coal mine near Cologne, West Germany. The excavator is operated by a crew of five, moving up to 110,000 cubic meters of coal or earth every day. Each machine is 220 meters in length, 85 meters high, with a gross weight of 13000 tons. It is capable of moving at speeds of up to 10 meters per minute. Each bucket on the excavator's wheel is large enough to hold a small car. The vast scale of the excavator means that it has to be constructed on site, taking around two years to complete.