Mirny Diamond Mine, Siberia



The Mirny Diamond Mine is 525m deep and has a diameter of 1200m. It was the first, and one of the largest, diamond Pipes in the USSR. It is now abandoned. While it was still operational, it would take two hours for trucks to drive from the top to the bottom of the mine.

Great Blue Hole, Belize



The Great Blue Hole is an underwater sinkhole off the coast of Belize. The hole is 1,000 feet across and 400 feet deep. It was formed as a limestone cave during the last iceage.

Bingham Canyon Mine, Utah



The Bingham Canyon Mine is a copper mine in the Oquirrh mountains, Utah. The mine is 0.75 mile (1.2 km) deep, 2.5 miles (4 km) wide. It is the world’s largest manmade excavation.

Monticello Dam, California



The Monticello Dam is a dam in Napa County, California, United States most noted for its large circular spillway with a rate of 48,400 cubic feet per second.