Leaning Tower of Pisa

he 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 tower presently leans to the southwest.

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^[1]. This means that the top of the tower is 3.9 meters from where it would stand if the tower were perfectly vertical.^[2]

Hagia Sophia

Hagia Sophia (Greek: Αγία Σοφία; "Holy Wisdom", Turkish: Ayasofya, Latin: Sancta Sophia or Sancta Sapientia) is a former patriarchal basilica, later a mosque, now a museum, in Istanbul, Turkey. Famous in particular for its massive dome, it is considered the epitome of Byzantine architecture. It was the largest cathedral ever built in the world for nearly a thousand years, until the completion of the Medieval Seville Cathedral in 1520.

The current building was originally constructed as a church between 532 and 537 AD on the orders of the Byzantine Emperor Justinian, and was in fact the third Church of the Holy Wisdom to occupy the site (the previous two had both been destroyed by riots). It was designed by two architects, Isidore of Miletus and Anthemius of Tralles. The Church contained a large collection of holy relics and featured, among other things, a 50 foot (15 m) silver iconostasis. It was the patriarchal church of the Patriarch of Constantinople and the religious focal point of the Eastern Orthodox Church for nearly 1000 years.

In 1453, Constantinople was conquered by the Ottoman Turks and Sultan Mehmed II ordered the building to be converted into a mosque. The bells, altar, iconostasis, and sacrificial vessels were removed, and many of the mosaics were eventually plastered over. The Islamic features - such as the mihrab, the minbar, and the four minarets outside - were added over the course of its history under the Ottomans. It remained as a mosque until 1935, when it was converted into a museum by the Republic of Turkey.

For almost 500 years the principal mosque of Istanbul, Hagia Sophia served as a model for many of the Ottoman mosques such as the Sultan Ahmed Mosque (Blue Mosque of Istanbul), the Şehzade Mosque, the Süleymaniye Mosque, and the Rüstem Pasha Mosque.

Although it is sometimes referred to as Saint Sophia (Greek for wisdom), the Greek name in full is Ναός τῆς Ἁγίας τοῦ Θεοῦ Σοφίας, Church of the Holy Wisdom of God, and it was dedicated to the Holy Wisdom of God rather than a specific saint named Sophia.

Porcelain Tower of Nanjing

The Porcelain Tower (or Porcelain Pagoda) of Nanjing (Chinese: 南京陶塔; pinyin: Nánjīng Táotǎ), also known as Bao'ensi (meaning "Temple of Gratitude"), is a historical archaeological site located on the south bank of the Yangtze in Nanjing, China. It was constructed in the 15th century as a Buddhist pagoda, but was mostly destroyed in the 19th century during the course of the Taiping rebellion. However, the tower is now under reconstruction once again.^[1]

The Great Wall of China (simplified Chinese: 长t; traditional Chinese: 長城; pinyin: Chángchéng; literally "Long wall") or (simplified Chinese: 万里长城; traditional Chinese: 萬里長城; pinyin: Wànlǐ Chángchéng; literally "The long wall of 10,000 Li (里)"^[1]) is a series of stone and earthen fortifications in China, built, rebuilt, and maintained between the 6th century BC and the 16th century to protect the northern borders of the Chinese Empire from Xiongnu attacks during the rule of successive dynasties. Several walls, referred to as the Great Wall of China, were built since the 5th century BC. The most famous is the wall built between 220–200 BC by the first Emperor of China, Qin Shi Huang; little of it remains; it was much farther north than the current wall, which was built during the Ming Dynasty.^[2]

The Great Wall stretches over approximately 6,400 km (4,000 miles)^[3] from Shanhaiguan in the east to Lop Nur in the west, along an arc that roughly delineates the southern edge of Inner Mongolia, but stretches to over 6,700 km (4,160 miles) in total.^[4] At its peak, the Ming Wall was guarded by more than one million men.^[5] It has been estimated that somewhere in the range of 2 to 3 million Chinese died as part of the centuries-long project of building the wall.^[6]

Taj Mahal

The Taj Mahal (pronounced /tɑʒ mə'hɑl/) (Persian: تاج محل), is a mausoleum located in Agra, India, that was built under Mughal Emperor Shah Jahan in memory of his favorite wife, Mumtaz Mahal.

The Taj Mahal (also "the Taj") is considered the finest example of Mughal architecture, a style that combines elements from Persian, Turkish, Indian, and Islamic architectural styles. In 1983, the Taj Mahal became a UNESCO World Heritage Site and was cited as "the jewel of Muslim art in India and one of the universally admired masterpieces of the world's heritage."

While the white domed marble and tile mausoleum is most familiar, Taj Mahal is an integrated symmetric complex of structures that was completed around 1648. Ustad Ahmad Lahauri is generally considered to be the principal designer of the Taj Mahal.^[1]

Colosseum

The Colosseum or Coliseum, originally the Flavian Amphitheatre (Latin: Amphitheatrum Flavium, Italian Anfiteatro Flavio or Colosseo), is an elliptical amphitheatre in the centre of the city of Rome, Italy, the largest ever built in the Roman Empire. It is one of the greatest works of Roman architecture and Roman engineering.

Occupying a site just east of the Roman Forum, its construction started between 70 and 72 AD under the emperor Vespasian and was completed in 80 AD under Titus, with further modifications being made during Domitian's reign (81–96).^[1] The name "Amphitheatrum Flavium" derives from both Vespasian's and Titus's family name (Flavius, from the gens Flavia).

Originally capable of seating around 50,000 spectators, the Colosseum was used for gladiatorial contests and public spectacles. It remained in use for nearly 500 years with the last recorded games being held there as late as the 6th century. As well as the traditional gladiatorial games, many other public spectacles were held there, such as mock sea battles, animal hunts, executions, re-enactments of famous battles, and dramas based on Classical mythology. The building eventually ceased to be used for entertainment in the early medieval era. It was later reused for such varied purposes as housing, workshops, quarters for a religious order, a fortress, a quarry and a Christian shrine.

Although it is now in a ruined condition due to damage caused by earthquakes and stone-robbers, the Colosseum has long been seen as an iconic symbol of Imperial Rome. Today it is one of modern Rome's most popular tourist attractions and still has close connections with the Roman Catholic Church, as each Good Friday the Pope leads a torchlit "Way of the Cross" procession to the amphitheatre.^[2]

The Colosseum is also depicted on the Italian version of the five-cent euro coin.

Stonehenge

Stonehenge is a prehistoric monument located in the English county of Wiltshire, about 3.2 kilometres (2.0 mi) west of Amesbury and 13 kilometres (8.1 mi) north of Salisbury. One of the most famous prehistoric sites in the world, Stonehenge is composed of earthworks surrounding a circular setting of large standing stones. Archaeologists believe that the standing stones were erected around 2200 BC and the surrounding circular earth bank and ditch, which constitute the earliest phase of the monument, have been dated to about 3100 BC. The site and its surroundings were added to the UNESCO's list of World Heritage Sites in 1986 in a co-listing with Avebury henge monument, and it is also a legally protected Scheduled Ancient Monument. Stonehenge itself is owned by the Crown and managed by English Heritage while the surrounding land is owned by the National Trust.^[1][2]

New archaeological evidence found by the Stonehenge Riverside Project indicates that Stonehenge served as a burial ground from its earliest beginnings.^[3] The dating of cremated remains found that burials took place as early as 3000 B.C, when the first ditches were being built around the monument. Burials continued at Stonehenge for at least another 500 years when the giant stones which mark the landmark were put up. According to Professor Mike Parker Pearson, head of Stonehenge Riverside Project:^[4]

Stonehenge was a place of burial from its beginning to its zenith in the mid third millennium B.C. The cremation burial dating to Stonehenge's sarsen stones phase is likely just one of many from this later period of the monument's use and demonstrates that it was still very much a domain of the dead.