Mexicali Blues

More than 18,000 people stripped down and bared it all in Mexico City's vast main square Sunday for U.S. photographer Spencer Tunick's biggest nude shoot yet. The volunteers formed a sea of flesh that Tunick snapped from balconies and a small crane in the morning light.

The Brooklyn, New York, artist has become famous for photographing thousands of naked people in public settings worldwide, from London and Vienna to Buenos Aires and Buffalo. "I just create shapes and forms with human bodies," Tunick said.

For Tunick's first photo, the models stood upright and gave a military-like salute to their national flag. In another, they lay down to form a blanket of flesh around a naked man in a wheelchair. Between shots, they burst out into verses of Mexican folk songs such as "Cielito Lindo."

Public nudity is hardly a novelty in Mexico City, where protesters often march through the streets wearing only their underwear or nothing at all.