A man sits outside a closed restaurant in downtown Mexico City April 30, 2009. Mexico began shutting down parts of its economy on Thursday to slow the spread of a new flu strain as officials urged increased worldwide precautions against an imminent pandemic.

REUTERS/Jorge Dan

A man takes a photo as members of the Republic of Singapore Air Force (RSAF) Black Knights aerobatic team form a heart shape using smoke trails during a performance at the Singapore Air Show in Singapore February 19, 2008.

REUTERS/Vivek Prakash

Sgt. William Olas Bee, a U.S. Marine from the 24th Marine Expeditionary Unit, has a close call after Taliban fighters opened fire near Garmser in Helmand Province of Afghanistan May 18, 2008. The Marine was not injured.

REUTERS/Goran Tomasevic