Philadelphia is home to several monuments dedicated to the men and women who died while in military service, including the Tomb of the Unknown Soldier, located in Washington Square.

In 1682, William Penn's surveyor, Thomas Holme, laid out the city grid to include five planned squares, one of which was Southeast Square at Locust and Sixth Streets. For much of the 18th century, this square was a grazing land and a potter's field. During the Revolutionary War, it was used as a burial ground for fallen colonial soldiers. Many victims of the yellow-fever epidemics of the late 1700s were also interred in the square.

The land was redeveloped and renamed Washington Square in honor of the first president in 1825. Philadelphia architect William Strickland designed a "Washington Monument" for the square. Although the cornerstone was laid in 1833, the monument itself was never erected. In 1954, the Tomb of the Unknown Soldier was built on the same grounds - it features a statue of George Washington and an eternal flame.