In this large, well-defined space, known worldwide as Piazza dei Miracoli, the main monuments are in harmony with each other. Nothing was left to chance and, in fact, if you look at the square from above, you can see that the Baptistery and the Cathedral are perfectly aligned with each other. The tower is decentralised by a few degrees with respect to the Cathedral and the Baptistery: this placement allows the sunlight to fall exactly in the centre of the Cathedral's dome, on the main altar, at dawn on 25 December, the winter solstice.
The Leaning Tower of Pisa, so well-known throughout the world because of its leaning position, is the bell tower of the cathedral of Santa Maria Assunta, Pisa Cathedral. It is 58 metres high and was built over the space of two centuries, between the 12th and the 14th century. It has curved lines, circles of blind arcades and six floors of loggias, but there was no certainty about the identity of the architect who designed it for a long time. It is thought that Bonanno Pisano designed it, although some scholars point to the architect Gherardi. What is certain is that Giorgio Vasari in his work Vite (Lives) defines the builders of the Tower of Pisa as "amateurs thrown in at the deep end", referring to Bonanno Pisano. In 1275, it was Giovanni Pisano who added three new floors, also in an attempt to straighten the tower. The famous leaning is caused by a subsidence of the ground beneath it, which occurred after the building of the first three floors.
In the bas-relief above the entrance door, you can admire the zodiac symbol of Aries, which distinguishes the entire Piazza dei Miracoli, as Pisa celebrated New Year on 25 March, the spring equinox, the day on which a solemn mass is still held today in the Cathedral. The structure of the bell tower of Pisa includes two rooms, one at the base of the tower, known as the Sala del Pesce (Room of Fish), without a ceiling, while the other is the bell chamber in the seventh ring. The chamber contains seven bells, one for each musical note. The bell of San Ranieri (Saint Rainerius) is associated with the musical note D ("re" in the Italian musical scale), also called the bell of justice or the traitor's bell, because it rang every time a traitor was sentenced to death. The bell is remembered for the fate of Count Ugolino, mentioned by Dante. He had been named dictator of the city of Pisa and had negotiated unfavourable conditions with Florence, giving up numerous many territories. For this reason, he was left to starve in the Gualandi tower with his children.
The tower was also an important scientific development tool: legend has it that Galileo Galilei used it to study the speed of descent of masses.