39. The Leaning Tower of Pisa

Location: Pisa, Italy

Year of Fail: 1178

Originally angled 5.5 degrees, the tower’s top is horizontally displaced almost thirteen feet from where it would be were the tower perfectly vertical. Constructed in three stages over 177 years, the tower began to sink in 1178 due to a major initial design flaw: a thin foundation set in unstable subsoil. To compensate for the fact that one side of the tower sunk lower, the engineers working on the structure in 1272 built upper floors with one side taller than the other. Though all floors were completed in 1372, strengthening of the structure to ensure the tower doesn’t topple has been a routine practice since.