Because Ubaid, Sumer, Akkad, Assyria and Babylon civilizations all emerged around the Tigris-Euphrates, the theory that Mesopotamia is the cradle of civilization is widely accepted.
If you Google for washington monument height, the first listing you see is for a page about the monument at greatbuildings.com. Note that the page mentions that the monument has a base of 55 feet and a height of 555 feet, in keeping with what they call the standard Egyptian proportion of 10:1 height to base.
Monument Under Siege. 1  The Washington Monument in Washington, DC, is a 555-foot obelisk that was erected as a tribute to the United Statesâ first president, George Washington. But it has not always been a place for tribute and celebration.