Contractors for the U.S. Army Corps of Engineers Pittsburgh District move a 10-ton anchor block into position to install more safety buoys to increase warning visibility at the Allegheny River Lock and Dam 2 in Pittsburgh, Pennsylvania, June 10, 2021. The Pittsburgh District recently added horizontal buoys on the Allegheny and at the Dashields Lock and Dam on the Ohio River to provide even more visible signs to warn recreational boaters from going over the dam. The dams on the Allegheny River and at Dashields are submerged, also known as fixed crest dams, which make them difficult to see from upstream. (U.S. Army Corps of Engineers Pittsburgh District photo by Michel Sauret)