Our Spectacular Planet

The Great Blue Hole is a large underwater sinkhole off the coast of Belize. It lies near the center of Lighthouse Reef, a small atoll 100 kilometres (62 mi) from the mainland and Belize City. The hole is circular in shape, over 300 metres (984 ft) across and 125 metres (410 ft) deep. What is a sinkhole? The sinkhole was formed as a limestone cave system during the last glacial period when sea ...

Buried a thousand feet (300 meters) below Naica mountain in the Chihuahuan Desert, the cave was discovered by two miners excavating a new tunnel for the Industrias Peñoles company in 2000. The cave contains some of the largest natural crystals ever found: translucent gypsum beams measuring up to 36 feet (11 meters) long and weighing up to 55 tons. "It's a natural marvel," said García-Ruiz, of the University of Granada in Spain. To ...

The desert is a land of extremes: extreme heat and extreme dryness; sudden flash floods and cold nights. Because deserts are such a harsh environment, deserts often have names likes "Death Valley," "the empty quarter," and "the place from where there is no return." Deserts are usually very, very dry. Even the wettest deserts get less than ten inches of precipitation a year. In most places, rain falls steadily throughout the year. ...