Maiden's Tower (Turkish: K?z Kulesi), also known in the ancient Greek and medieval Byzantine periods as Leander's Tower (Tower of Leandros), sits on a small islet located in the Bosphorus strait off the coast of üsküdar in Istanbul, Turkey.

 

Maiden's Tower was first built by the ancient Athenian general Alcibiades in 408 BC to control the movements of the Persian ships in the Bosphorus strait. Back then the tower was located between the ancient cities of Byzantion and Chalcedon. The tower was later enlarged and rebuilt as a fortress by the Byzantine emperor Alexius Comnenus in 1110 AD, and was rebuilt and restored several times by the Ottoman Turks, most significantly in 1509 and 1763. The most recent facelift was made in 1998. Steel supports were added around the ancient tower as a precaution after the 17 August 1999 earthquake.

 

Used as a lighthouse for centuries, the interior of the tower has been transformed into a popular café and restaurant, with an excellent view of the former Roman, Byzantine and Ottoman capital. Private boats make trips to the tower several times a day.

 

The Galata Tower (Turkish: Galata Kulesi), also called Christea Turris (Tower of Christ) by the Genoese and Megalos Pyrgos (The Great Tower) by the Byzantines, is located in Istanbul, Turkey, to the north of the Golden Horn. One of the city's most striking landmarks, it is a huge, cone-capped cylinder that dominates the skyline on the Galata side of the Golden Horn.

 

The Galata Tower was built as Christea Turris in 1348 during an expansion of the Genoese colony in Constantinople. It was the apex of the fortifications surrounding the Genoese citadel of Galata. The current tower should not be confused with the old Tower of Galata, an original Byzantine tower, named Megalos Pyrgos, which controlled the northern end of the massive sea chain that closed the entrance of the Golden Horn. This tower was on a different site and was largely destroyed during the Fourth Crusade in 1204.

 

The 66.90 m tower (62.59 m without the ornament on top) was the city's tallest structure when built. In 1638, Hezarfen Ahmet ?elebi flew as an early aviator using artificial wings from this tower over the Bosphorus to the slopes of üsküdar on the Anatolian side.

Hagia Sophia, Holy Wisdom, Turkish Ayasofya) 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 and one of the most beautiful buildings in the world. It was the largest cathedral 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 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 focus point of the Orthodox Byzantine Empire 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 four minarets outside, the mihrab and minbar - 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 secular 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.

The Bosphorus Bridge also called the First Bosphorus Bridge (Turkish: Boğaziçi Koprüsü or 1. Boğaziçi Koprüsü ) is a bridge in Istanbul, Turkey spanning the Bosphorus strait (Turkish: Boğaziçi). The bridge is located between Ortaköy (European side) and Beylerbeyi (Asian side). It is a gravity anchored suspension bridge with steel pylons and inclined hangers. The aerodynamic deck is hanging on zigzag steel cables. It is 1,560 m long with a deck width of 39 m. The distance between the towers (main span) is 1,074 m (World rank: 13th) and their height over road level is 105 m. The clearance of the bridge from sea level is 64 m. It was the 4th longest suspension bridge in the world when completed in 1973, and the longest outside the United States of America.