Ships, cigarette butts, trash, human waste and even bodies have been known to float through Baltimore's Inner Harbor, but this month, some brave (or crazy) souls decided to dive in.

A YouTube video posted July 14 shows at least 15 people, apparently tourists, taking dips in the harbor as many Baltimoreans look on.

“They're from Chicago,” said one onlooker. “They don't know no better.”

Adam Lindquist, director of the Waterfront Partnership's Healthy Harbor Initiative, said while there are no regulations on swimming in the harbor, he would not advise it.

“Our biggest pollution problem in the Baltimore harbor is the raw sewage that's overflowing or leaking from the city's system,” Lindquist said.

—Brittany Britto