The Washington Monument is an obelisk on the National Mall in Washington, D.C., built to commemorate George Washington, once commander-in-chief of the Continental Army and the first President of the United States. Height: 555′
Construction started: 1848
Opened: October 9, 1888 "Wikipedia"

It is still the tallest free standing masonary structure in the world. According to our guide there is no mortar or steel to support this height. As a side note, at the time of this picture the evelvator was broken and no one is able to get to the top. And he added that officials say it should be back in service by 2019...which means in 2021 in "Washington"!