Pisa Tower : 
WHO?
WHEN ?
HOW AND WHY ?
She was built in 1173
After a year it was founded in 1174
and opened in 1372
There were renovations between 1933 and 1935
The architect of the tower was
Boanno Pisano, Guillaume of Inspruck and Giovanni di Simone
Pisano was born at Pisa and was an architect, he was dead in his hometown
The other architect like Guillaume of Inspruck was of german origin and Giovanni di Simone was of Italy origin
The Pisa tower has a Roman style as architecture, the materials were marble
The tower is 55.86 meters high on the south side and 56.71 m on the north side, due to its inclination, and has an external diameter of 15.5 meters
The tower began to tilt a few years after its construction, it was located on a fairly loose ground
Looking at it from the east or the west, "we see that it leans less up than down, because its aplomb has visibly been gradually corrected during its construction. Even today, she leans little by little
WHERE ?
It is located near the apse of the cathedral Our Lady of the Assumption of Pisa
She is one of the monuments of "piazza dei Miracoli" (the "Square of Miracles")
It is located in Europe, in
Itale in the city of Pisa
)
Marble: 
Pisa tower interior: 