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
The Flavian Amphitheater
Emperor Vespasian, founder of the Flavian Dynasty, started construction of the Colosseum in 72 AD. It was completed in 80 AD, the year after Vespasian's death.
The huge amphitheater was built on the site of an artificial lake, part of Nero's huge park in the center of Rome which also included the Golden House (Domus Aurea) and the nearby Colossus statue. This giant statue of Nero gave the building its current name.
The elliptical building is immense, measuring 188m by 156m and reaching a height of more than 48 meters (159 ft). The magnificent structure was clad in marble and 160 larger-than-life statues graced the arches on the upper floors.
The Colosseum could accommodate some 55,000 spectators who entered the building through no less than 80 entrances. Above the ground are four stories, the upper story contained seating for lower classes and women
Velarium
The Colosseum was covered with an enormous awning known as the velarium. This protected the spectators from the sun. It was attached to large poles on top of the Colosseum and anchored to the ground by large ropes. A team of about one thousand men was used to install the awning.
Inauguration
Hundred-day games were held by Titus, Vespasian's successor, to mark the inauguration of the building in 80 AD. In the process, some nine thousand wild animals were slaughtered.