The Leaning Tower of Pisa is easily one of the most famous structures of the world. Italy’s prominent landmark, while being breathtakingly beautiful, is also well-known for its visible architectural flaw. Did you know, however, that the structure was actually the result of a human mistake? One little miscalculation made in the 11th century gave the world this unique 14,500-tonne tower. Explore the truth behind this beautiful engineering mistake in this video.