Washington Square was originally something of a potter's field, where dead soldiers and POWs of the Revolutionary War were buried. Supposedly, there are still quite a few buried beneath your feet as you walk through the park. At one end is a statue of George Washington, which is the frontal piece for a memorial to an unknown soldier from his army. The plaques will tell you more.
Somehow I kept finding myself at this park everyday while in Philadelphia. It helped to soothe my nerves after dodging cars while crossing the busiest streets near there. The moment I would walk within the walls of this park, I felt calm and safe.
Washington Square is an oasis with plenty of benches and lovely foliage to stare at as you slip into a sort of peaceful trance after a long day of walking. The west side of the park has the Tomb of the Unknown Soldier. It's amazing to think that thousands of people were buried in this park during the 18th and 19th centuries. Don't let that scare you away from spending time here though. It really does look like a cemetery.
When William Penn first planned Philadelphia, he wanted a few things: streets laid out in grids (nice job), and numerous parks throughout the city. One such park is Washington Square, renamed for George Washington in the early 19th century.
Washington Square is not a huge park, but it includes the Tomb of the Unknown Soldier, dedicated to those who died in the American Revolution. It's surrounded by rows of state/colonial flags. A fine monument, and a place to reflect on all that happened in late 18th century America.
This is a very tranquil and beautiful spot in the heart of the old city. There is a memorial to the War of Independence there.