The Leaning Tower of Pisa（Italian：Torre pendente di Pisa）or simply The Tower of Pisa（La Torre di Pisa）is the campanile，or freestanding bell tower，of the cathedral of the Italian city of Pisa。It is situated behind the Cathedral and it is the third structure by time in Pisa's Piazza del Duomo（Cathedral Square）。
Although intended to stand vertically，the tower began leaning to the southeast soon after the onset of construction in 1173 due to a poorly laid foundation and loose substrate that has allowed the foundation to shift direction。
The height of the tower is 55.86 m（183.27 ft）from the ground on the lowest side and 56.70 m（186.02 ft）on the highest side。The width of the walls at the base is 4.09 m（13.42 ft）and at the top 2.48 m（8.14 ft）。Its weight is estimated at 14，500 tonnes。The tower has 296 or 294 steps；the seventh floor has two fewer steps on the north-facing staircase。The tower leans at an angle of 3.97 degrees。This means that the top of the tower is 3.9 meters from where it would stand if the tower were perfectly vertical。
比萨斜塔（意大利语：Torre pendente di Pisa或La Torre di Pisa）是意大利比萨城大教堂的独立式钟楼，位于比萨大教堂的后面，是奇迹广场的三大建筑之一。
钟楼始建于1173年，设计为垂直建造，但是在工程开始后不久便由于地基不均匀和土层松软而倾斜，1372年完工，塔身倾斜向东南。
比萨斜塔从地基到塔顶高58.36米，从地面到塔顶高56.7米，钟楼墙体在地面上的宽度是4.09米，在塔顶宽2.48 米，总重约14，500吨。比萨斜塔有296或294步台阶——在第7层向北的地方少了两步台阶。目前，此塔的有3.97度的倾斜，也就是说，塔的顶层偏离地基外3.9米。
比萨斜塔是比萨城的标志，1987年它和相邻的大教堂、洗礼堂、墓园一起因其对11世纪至14世纪意大利建筑艺术的巨大影响，而被联合国教育科学文化组织评选为世界遗产。
Cathedral n。大教堂
Vertically adj。垂直地
Leaning adj。倾斜的
Onset n。（爆发性的）开始
（尤指不愉快的事），突然降临