Tower of Pisa stands at 60 metres and until 1990 was leaning at about a 10 degree angle.
Although it was designed to be perfectly vertical, it started to lean during construction.
The Colosseum is probably the most impressive building of the Roman Empire. Originally known as the Flavian Amphitheater, it was the largest building of the era.
The monumental structure has fallen into ruin, but even today it is an imposing an