Your construction-picture issue was great. I have never seen anything like some of the pictures I viewed there. I respect the efforts of all involved to ensure safe practices were shown in all pictures. However, I note two safety questions about two of the pictures. On page 30, there is a great picture of underground construction in New York City. I enjoyed this picture immensely until I realized that the worker was standing on top of the rail. In my eight years at BNSF Railway, I learned that one should never step on the head of the rail. It is
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.