Bologna is called "La Turrita", which means packed with towers, because of its countless towers. Only fewer than 20 can still be seen today and among them Torre Asinelli and Tore Garisenda are the most famous and considered to be the emblems of the town of Bologna.
Between the 12th and the 13th centuries the number of towers in the city was very high, possibly up to 180 or 200. The reason for the construction of so many towers are not completely clear. One hypothesis is that the richest families used them for ofensive and difensive purposes. Besides the towers there are still preserved fortified gateways in the city, so-called "tottesotti", that corespond to the gates of the 12th century city walls (Mura dei Torresotti or Cerchia dei Mille) which itself has been almost completely destroyed.
During the 13th century many towers were taken down or demolished and other simply collapsed. Some of the towers have subsequently been utilized as prisons or even residential buildungs. The last demolitions of the towers took place during the first half of the 20th century.
The construction of the towers was quite onerous, the usage of serfs not withstanding. To build such an tower with a height of 60 metres would have required between 3 and 10 years of work. Each tower had a square cross section with foundations between 5 and 10 meters deep, reinforced by polles hammered into the ground and covered with pebble and lime. The tower base was made of big blocks of selenite stone. Usually some holles were left in the outer walls as well as bigger hollows in the selenite to support scaffoldings and to allow for later coverings and constructions, generally on the basis of wood.
Fondest memory: Conversely, Asinelli tower is considered as a heavy one, in fact it weights 8,500 tonsand features a quite low barycentre. In 1488, a military loggia, Rocchetta, was added to the tower.
Garisenda tower is co-called "leaning tower".
Favorite thing: When you finish with the visit of the two squares I descibed before you can go to visit the Torre degli Asinelli. You must take the road Via Ugo Bassi and you must walk until the end of it, there you can see the two towers. If you want you can go up on the tallest tower (the ticket is sold for 3.00 € and it's open all day until 6pm), because is very beautiful take a look of this wonderful city from there (the tower is a bit pending, so be careful when you'll see down).
Favorite thing: Visit The Two Towers. From the Asinelli Tower (the highest in the city) you have a beautiful panorama of Bologna.