Marines march in grueling Afghan sun for July 4

Taliban militants were nowhere in sight as the columns of U.S. Marines walked a third straight day across southern Afghanistan. But the desert heat proved an enemy in its own right, with several troops falling victim Saturday to temperatures topping 100 degrees Fahrenheit.
The Marines carry 50-100 pounds (23-45 kilograms) on their backs. But because they are marching through farmland on foot, they can't carry nearly as much water as their thirst demands...

PICTURE LEFT:U.S. Marine Cpl. Brian Knight, of Cincinnati, Ohio, with the 2nd Marine Expeditionary Brigade, 1st Battalion 5th Marines, pauses briefly in the heat to rest with his heavy pack filled with mortar equipment, ammunition, food, and water in the Nawa district in Afghanistan's Helmand province Saturday, July 4, 2009. Taliban militants attacked a U.S. coalition base in eastern Afghanistan on Saturday with an explosives-laden truck that blew up outside the gates, sparking a two-hour gunbattle and killing two American troops, officials said.(AP Photo/David Guttenfelder)