Piazza dei Miracoli, known as Piazza del Duomo, is the most important artistic and tourist centre of Pisa. It is recognised as part of the World Heritage by UNESCO since 1987, there are great works of the European Romanic Age : the cathedral, the Baptistery ,  the Cemetery and the leaning tower , which are the main monuments of the religious life of the city and just known as "miracles" for their beauty and originality .

The Leaning Tower is the bell tower of the Cathedral. the ground underneath the tower has yielded and moved slightly , making it tilt a few degrees. It is a tower built during over two centuries (in three different working stages) from the end of the twelfth century. The heart of the monumental complex is the Cathedral of Santa Maria Assunta, the medieval cathedral. It is also a Primaziale , being the Archbishop of Pisa a Primate. It is a church with five naves with a transept with three naves. The building, like the bell tower, has sunk slightly in the soil, and some failures are visible in its aspect , such as level differences between the nave by Buscheto and the work prolongation by Rainaldo (the bays to the west and the frontage) .

The baptistery dedicated to San Giovanni Battista , stands opposite the West Front of the Cathedral. The building was begun in the mid-twelfth century, the inner space , strangely simple and without decoration, also has an excellent acoustics. It is the largest baptistery in Italy: its circumference is 107.25 m. The Monumental Cemetery is located on the northern edge of the square. It is essentially a cemetery enclosed by walls . From 1945 up to now restoration work are still ongoing , which incidentally led to the recovery of precious sinopie .