Our Pick
Posted on @rawstates
Colorado Lagoon, the swimming hole locals called Polio Pond
1920
Long Beach, California
Tracie Hall · CC BY-SA 2.0 · Wikimedia Commons
Dredged out of the Los Cerritos Wetlands in the 1920s as a tidal swimming lagoon, it collected so much street runoff that Long Beach children grew up calling it Polio Pond. The county started hauling out contaminated sediment in 2009 and the second phase of the cleanup is still running. People swim and sail model boats there again.
That was 1 of the hidden places.
Location: documented spot
This place has its own thread on r/rawstates
Read what people are saying about it, or add your own.