Hundreds plunge in Chicago River for first official swim in nearly 100 years

Group participates in previously unthinkable mile-long swim after US made key progress to clean polluted rivers

Hundreds of people plunged into the Chicago River's chilly waters on Sunday as part of the first organized swim in the river for nearly 100 years, a previously unthinkable act in what was once one of the most befouled waterways in the world.

About 300 people, some wearing wetsuits, jumped into the Chicago River for a mile-long looping swim on an early, overcast midwest morning, a feat made possible by the often unseen but crucial progress the US has made in the past half century in cleaning its rivers of toxic pollution.