Our Pick
Posted on @rawstates
The Braddock dam was built in a dry dock and floated into place
2004
Braddock, Pennsylvania
Public domain · Wikimedia Commons
The Army Corps replaced a fixed crest dam here that was nearly a century old, and did it without draining the river. Two hollow concrete segments, the larger weighing 11,600 tons, were cast in an off site dry dock, floated down the Monongahela and set onto a prepared foundation of sheet pile walls and drilled shafts. Work ran from 1999 to May 2004 and cost about 107 million dollars. The lock chambers beside it date to 1953, and the whole works replaced an 1841 lock and dam upriver at Port Perry.
That was 1 of the hidden places.
Location: historic site
This place has its own thread on r/rawstates
Read what people are saying about it, or add your own.