Eric Walker added Bridges and Infrastructure in the United States to Infrastructure, and added Infrastructure to Civil engineering

Eric Walker added America's bridges are falling apart faster than expected to Infrastructure in the United States, and added Infrastructure in the United States to United States and Infrastructure

Eric Walker added Golden Gate Bridge and Morandi Bridge and a number of links to Bridges, and added Bridges to Infrastructure

Eric Walker added Metropolitan Area Outer Underground Discharge Channel and Infrastructure and a number of links to Civil engineering, and added Civil engineering to Engineering