Rebar before concrete
FOLSOM, Calif. -- Working in a maze of a steel rebar, contractors for the U.S. Army Corps of Engineers Sacramento District construct a support system for concrete placement for the auxiliary spillway at the Folsom Dam Joint Federal Project here, June 14, 2012. The Folsom Dam Joint Federal Project is a joint effort of the Corps, U. S. Bureau of Reclamation, the Central Valley Flood Protection Board and the Sacramento Area Flood Control Agency to improve the safety of the current dam and reduce flood risk for the greater Sacramento area. (U.S. Army Corps of Engineers photo by Michael J. Nevins). Original public domain image from Flickr