555 -- height, in feet, of the Washington Monument, the tallest structure in Washington, D.C. 575 -- height, in feet, of the new Three Gorges Dam in China (which is also wider than 100 Washington Monuments standing edge to edge) 4.3 million -- cubic meters of concrete needed to build the Panama Canal 26.4 million -- cubic meters of concrete needed to build the Three Gorges Dam 80 -- number of cracks, up to 8 feet in depth, that have appeared in the Three Gorges Dam since its construction 1 53 -- number of engineers and other experts in China …