Across the street from Independence Hall in Philadelphia, the Liberty Bell, with it's famous crack, is still heavily protected. 2 heavy marble walls, designed for bomb protection.
After 75 years the famous bell, hanging form a beam of Elm, just a foot off the ground, fails. The Elm rotted and attacked by insects fails and the bell falls, and completely cracks in half. After 300 years, The Liberty Bell still sits half buried between it's blast walls in the middle of a dense forest that was Philadelphia.