Leaning Tower, Pisa, Italy

The campanile was constructed alongside the cathedral beginning on August 14, 1173, while Pisa was still an autonomous republic. The tower began to lean even during construction, after the first three stories were built, because of the soft and unstable soils it was built upon. Construction was halted for some time, but resumed in 1272, while builders attempted to counteract the tilt by altering construction. The construction paused again after 1284 because of battles between Pisa and Genoa. The tower was finally completed in 1372, after almost 200 years of off-and-on construction. The tilt became more extreme over time, until restoration stabilized it.