Leaning Tower of Pisa in the context of "Pisa Cathedral"

Pisa (/ˈpiːzə/ PEE-zə; Italian: [ˈpiːza] or [ˈpiːsa]) is a city and comune (municipality) in Tuscany, Central Italy, straddling the Arno just before it empties into the Ligurian Sea. It is the capital city of the Province of Pisa. Although Pisa is known worldwide for the Leaning Tower of Pisa, the city contains more than twenty other historic churches, and several medieval and Renaissance palaces, mostly facing each other on the avenues along the Arno ("Lungarno"). Much of the city's architecture was financed from its history as one of the Italian maritime republics.

The city is also home to the University of Pisa, which has a history going back to the 12th century, the Scuola Normale Superiore di Pisa, founded by Napoleon in 1810, and its offshoot, the Sant'Anna School of Advanced Studies.

Soil mechanics is a branch of soil physics and applied mechanics that describes the behavior of soils. It differs from fluid mechanics and solid mechanics in the sense that soils consist of a heterogeneous mixture of fluids (usually air and water) and particles (usually clay, silt, sand, and gravel) but soil may also contain organic solids and other matter. Along with rock mechanics, soil mechanics provides the theoretical basis for analysis in geotechnical engineering, a subdiscipline of civil engineering, and engineering geology, a subdiscipline of geology. Soil mechanics is used to analyze the deformations of and flow of fluids within natural and man-made structures that are supported on or made of soil, or structures that are buried in soils. Example applications are building and bridge foundations, retaining walls, dams, and buried pipeline systems. Principles of soil mechanics are also used in related disciplines such as geophysical engineering, coastal engineering, agricultural engineering, and hydrology.

This article describes the genesis and composition of soil, the distinction between pore water pressure and inter-granular effective stress, capillary action of fluids in the soil pore spaces, soil classification, seepage and permeability, time dependent change of volume due to squeezing water out of tiny pore spaces, also known as consolidation, shear strength and stiffness of soils. The shear strength of soils is primarily derived from friction between the particles and interlocking, which are very sensitive to the effective stress. The article concludes with some examples of applications of the principles of soil mechanics such as slope stability, lateral earth pressure on retaining walls, and bearing capacity of foundations.

The province of Pisa (Italian: provincia di Pisa) is a province in the Tuscany region of Italy. Its capital is the city of Pisa. With an area of 2,448 square kilometres (945 sq mi) and a total population of 421,642 (As of 2014), it is the second most populous and fifth largest province of Tuscany. It is subdivided into 37 comuni (sg.: comune).

With a history that dates to the Etruscans and Phoenicians, the province achieved considerable power and influence in the Mediterranean in the 12th and 13th centuries. Pisa, the provincial capital, is known for its Leaning Tower, and other historic landmarks that attract tourists.

The Pisa Baptistery of St. John (Italian: Battistero di San Giovanni) is a Catholic ecclesiastical building in Pisa, Italy. Construction started in 1152 under the direction of Diotisalvi (signed and dated) to replace an older baptistery. Completed in 1363 in a Gothic manner, it is part of the architectural ensemble and World Heritage Site of the Piazza dei Miracoli, alongside the Duomo di Pisa, its campanile, the famous Leaning Tower of Pisa, and the Camposanto.

The Piazza dei Miracoli (Italian: [ˈpjattsa dei miˈraːkoli]; 'Square of Miracles'), formally known as Piazza del Duomo ('Cathedral Square'), is a walled 8.87-hectare (21.9-acre) compound in central Pisa, Tuscany, Italy, recognized as an important center of European medieval art and one of the finest architectural complexes in the world. It was all owned by the Catholic Church and is dominated by four great religious edifices: Pisa Cathedral, the Pisa Baptistery, the Leaning Tower of Pisa (the cathedral's campanile or bell tower), and the Camposanto Monumentale ('Monumental Cemetery'). Partly paved and partly grassed, the Piazza dei Miracoli is also the site of the Ospedale Nuovo di Santo Spirito ('New Hospital of the Holy Spirit'), which now houses the Sinopias Museum (Museo delle Sinopie) and the Cathedral Museum (Museo dell'Opera del Duomo).

The square's popular name was coined by the Italian writer and poet Gabriele D'Annunzio who, in his novel Forse che sì forse che no (1910), described the square as the "prato dei Miracoli", or 'meadow of miracles'. It is also sometimes called the Campo dei Miracoli ('Field of Miracles'). In 1987, the whole square was declared a UNESCO World Heritage Site.