21015 The Leaning Tower of Pisa

  • Product no longer in production


  • Location: Pisa, Italy
  • Architect: Various
  • Style: Romanesque Tower/Goth Bell Chamber
  • Materials: Limestone, lime mortar, marble exterior
  • Type: Bell Tower
  • Size: 8 stories (56.4m/185 feet)
  • Angle of tilt: 3.97 degrees (3.9m/12'10") from vertical
  • Year: 1928-31


The Leaning Tower of Pisa (Torre pendente di Pisa) took almost 200 years to complete and has stood beside the Cathedral of Pisa for over 600 years. Thanks to its famous tilt, it has become one of the world's most recognizable architectural landmarks. The story behind the bell tower spans over 800 years of European history and provides a fascinating glimpse into a miracle of medieval engineering.

While the Tower of Pisa is most known for ”leaning”, it would still be a remarkable architectural structure without this famous feature. Constructed at a time when there was very little building of this kind being carried out in Europe, the intelligent use of columns and arches demonstrates an in-depth understanding of weight and load characteristics that was way ahead of its time.

What the architect overlooked however, was the clay-based soil and the need for a foundation capable of supporting a bell tower that would eventually weigh 16.000 tons (14.500 metric tons).

The eight-story tower was built with limestone and lime mortar, with an exterior covering of marble. Interestingly, the limestone is probably why the tower has not cracked and collapsed – the rock is flexible enough to withstand the pressures placed on it by the tilt. The bottom story of the tower is an arcade of 15 closed marble arches. Each of the following six stories contains 30 arches, while the final story, or bell-chamber, has 16 arches.


The identity of the Tower of Pisa’s first architect remains a mystery. For many years, the initial phase of the design work was attributed to Bonanno Pisano, a well-known 12th-century resident artist of Pisa. However, recent studies appear to indicate that an architect named Diotisalvi, who designed the baptistery, was also responsible for the tower. The second phase of construction is attributed to Giovani di Simone, who added four floors to the tower in 1275. Architect Tommaso di Andrea Pisano (1350-1372) was the architect who finished the work and succeeded in harmonizing the Gothic elements of the bell-chamber with the Romanesque style of the tower.