It was rainy the day that we visited but through the mist, in the distance, you can see the Pentagon.
The Tomb of the Unknowns (also known as the Tomb of the Unknown Soldier) is guarded 24 hours a day, 365 days a year, and in any weather by Tomb Guard sentinels(all volunteers). Here they are about to change the sentinel.
The next three shots are of the very impressive Memorial Amphitheatre completed in 1920. It is completely constructed of marble.
Interestingly, President Woodrow Wilson placed its cornerstone on Oct. 15, 1915 in which was placed a box containing:
The Declaration of Independence
The U.S. Constitution
U.S. Flag (1915)
Designs and plans for the amphitheater
L'Enfant's map design of the city of Washington, D.C.
Autograph of the amphitheater commission
One of each U.S. coin in use in 1915
One of each U.S. postage stamp in use in 1915
1914 map of Washington, D.C.
The Congressional Directory
Boyd's City Directory for the District of Columbia
Autographed photo of President Woodrow Wilson
The cornerstone dedication program
The Evening Star newspaper account of the ceremonies, and the campaign to build the Amphitheater
For more info on the cemetery click this link.