This is a picture of the Liberty Bell today
 

As the official bell of the Pennsylvania  State House (today called Independence Hall) the bell rang many times for public announcements, but its most famous ringing occurred on July 8, 1776 when it rang to announce the first public reading of the Declaration of Independence.

By 1846 a thin crack began to affect the sound of the bell. The bell was repaired in 1846 and rang for a George Washington birthday celebration, but the bell cracked again and has not been rung since. No one knows why the bell cracked either time.