Birthday Canyon in Greenland

Birthday Canyon in Greenland
This 2009 photo released by Extreme Ice Survey shows Birthday Canyon in Greenland furing the filming of “Chasing Ice.” The film, about climate change, follows National Geographic photographer James Balog across the Arctic as he deploys revolutionary time-lapse cameras designed to capture a multi-year record of the world’s changing glaciers. Birthday Canyon is approximately 150 feet deep. (AP Photo/Extreme Ice Survey, James Balog) Continue reading »

Grand Canyon Skywalk

Grand Canyon Skywalk

The Grand Canyon Skywalk is a transparent horseshoe-shaped cantilever bridge and tourist attraction in Arizona near the Colorado River on the edge of a side canyon in the Grand Canyon West area of the main canyon. USGS topographic maps show the elevation at the Skywalk’s location as 4,770 ft (1,450 m) and the elevation of the Colorado River in the base of the canyon as 1,160 ft (350 m), and they show that the height of the precisely vertical drop directly under the skywalk is between 500 ft (150 m) and 800 ft (240 m). Continue reading »

Arizona’s Antelope Canyon

Arizona's Antelope Canyon

Arizona’s Antelope Canyon taken by amateur photographer Gregory Boratyn. (Gregory Boratyn/Rex Features)

Glen Canyon Dam in Page, Arizona

Glen Canyon Dam in Page, Arizona

Water pours from river outlet tubes during an experimental high flow release from the Glen Canyon Dam in Page, Arizona, November 19, 2012. The total maximum release from the dam will reach approximately 42,300 cubic feet per second – 27,300 cfs of full-capacity powerplant releases and a bypass release through four river outlet tubes sending 15,000 cfs of water out over the Colorado River, according to an Interior Department statement. The release is part of a long-term protocol announced in May by Interior Secretary Ken Salazar to meet water and power needs and resolve problems with downstream sediment and non-native fish predation on the Colorado River below the dam. (Bob Strong/Reuters)