Since 1800, Washington, D.C. has been the seat of power in the United States of America.  Its many monuments honor centuries of achievement as well as the lives of individual Americans who have shaped the course of history.  The memorials to the Korean and Vietnam wars, along with the Arlington National Cemetery, are reminders of the dangers faced by our military men and women.  The Washington Monument rises 555 feet, and is the tallest structure in the Nation's Capitol and the world's tallest masonry structure.