The Liberty Bell is one of the most important symbols of the American revolutionary war. Its most important ringing took place in 1776, when the citizens were gathered to read the Declaration of Independence.
The museum is free and, apart from the Bell, you’ll find a lot of historic items of that time, including the Declaration of Independence itself. For souvenirs go to the National Constitution Center.
If you're a How I Met your Mother fan, try to resist from licking the bell :P
