Swimmers prepare to compete in the Little Red Lighthouse Race in the Hudson River. Photo by Capri Djatiasmoro.

There are plenty of good reasons not to jump into New York City’s Hudson River. Though the waterways surrounding Manhattan have historically been plagued by pollution, city authorities are now reporting the best water quality in over a century. Still, other hazards make swimming in the Hudson dangerous. Even so, thousands take part every year in events like NYC Swim’s Little Red Lighthouse Race, which give adventure-seekers a safe way to brave the elements.

Russ Finkelstein Reports.