He's about 2 feet high off a 4-foot ledge.

He's about 2 feet high off a 4-foot ledge.

PHILADELPHIA PA – No matter where people were Friday afternoon (April 24, 2009) in Center City Philadelphia, it seemed, the skateboarders were there too.

They were polite. They were quiet, except for the sound of their skate wheels rasping against concrete, asphalt, graniteĀ  and marble. They were careful to avoid nearby pedestrians. And they appeared omnipresent.

Few risks here except stumbling. Their challenge was just a curb.

Few risks here except stumbling. Their challenge was just a curb.