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.

“It’s overwhelming to see this happen, it’s unbelievable to see swimmers swim past us now,” said Doug McConnell, the main organizer of the event.

McConnell, a Chicago area native and co-founder of A Long Swim, had been pushing the city’s leadership for more than a decade to allow a swim in the river, the first such event since 1927, having witnessed the blossoming urban river swimming movement take hold in cities such as Paris, Munich and Amsterdam.