Whoa, how is that building standing up? The famous Leaning Tower of Pisa in Italy has been leaning for more than 800 years without falling! It took 199 years to build, starting in 1173. But 5 years in, as soon as they added the 3rd story, it started tilting. The tower is really heavy for its height -- 16 THOUSAND tons - and was built on soft clay. But builders kept adding on in hopes they could fix it. Now we're just hoping it won't fall over!