Udachnaya Pipe, Russia
The Udachnaya Pipe is a diamond mine in Russia. The owners of the mine plan to cease its operations in 2010 – in favor of underground mining. The mine was discovered in 1955 and is over 600 meters deep.
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.
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.