Courtesy of National September 11 Memorial & Museum Panels with 2,983 names of victims can be heated or cooled for the comfort of visitors. Photo by Nadine Post/ENR Sole surviving tree from 9/11. Related Links: At New York's New World Trade Center, Uncommon Cooperation Key Links Help Reshape Manhattan Below Grade at WTC Hub, a Transit Tango Tower Crews Get Royal Treatment Editorial: In Close Quarters, Spirit of Cooperation Reigns Slide Show: ENRs World Trade Center Saga Continues Port Authoritys World Trade Center Site All Coverage of Rebuilding Ground Zero Video: Progress in Rebuilding Ground Zero Video: An Overview of
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.