Thousand-Column Cistern
Located in Sultanahmet to the west of the Hippodrome, the cistern is the second biggest cistern of Istanbul after the Basilica Cistern. It was built in the 4th century during the reign of Constantine the Great, and historical sources attribute it to Philoxenus. 212 out of 224 original columns have remained up until today. During the renovation work small booths for vendors, a cafe, and exhibition areas were constructed as well.
Hagia Irene
Thought to be the oldest place of Christian worship in Istanbul, Hagia Irene is believed to be first built in the 4th century AD by the Byzantine Emperor Constantine I. It was originally constructed over the ruins of a pagan temple. Today it is said that the church was dedicated to a Saint Irene; however, Hagia Irene means "Divine Peace" in Greek, so it there is no such Saint in this story. Before the Hagia Sophia, The Hagia Irene served as the church of the Patriarchate. It still has its original atrium, five rows with built-in seats embracing the apse, and a great simple black cross on a gold background in the half-dome above the main narthex, which dates back from the Iconoclastic period when all figurative images were forbidden. It is also the only church that was not turned into a mosque after the conquest of Constantinople by the Ottomans in 1453. Today it is located within the Topkapi Palace complex, close to the Hagia Sophia and concerts of the Istanbul Music Festival are organized here due to its excellent acoustics. It is open as a museum every day except Monday but requires special permission for admission, requiring at least 10 people as visitors.

Caferağa Madrasa

Gülhane Park
“Gülhane” means “house of roses” in Turkish. It is an expansive park with different shades of green. The park was within the borders of Topkapı Palace, so it was not open to public until 1912. The park previously had a zoo inside; however, it was removed during the renovation process. Gülhane Park is also the place where the first statue of Atatürk - in Turkey - was erected in 1926. There is a teahouse inside the park with a beautiful view of the Bosphorus. After a tiring day, you can unwind under this relieving atmosphere.

Büyükada: The Big Island

Rumeli Fortress
Built in 1452 by Sultan Mehmed the Conqueror before he conquered Constantinople, the Rumeli Fortress had a strategic quality to control the sea traffic during the siege of the city in 1453. You can also see the Anadolu Fortress across on the Asian side of the Bosphorus. It was mainly used as a prison, especially for foreign prisoners of war, during 17th century. The Fortress was converted into a museum in 1958. The Fortress is open to visitors during the week except for Wednesdays from 9:00 to 16:30.
Anadolu Fortress
Built on the ruins of an old temple dedicated to Zeus by the Ottoman sultan Bayezid I between 1393 and 1394, the Anatolian Fortress is much smaller than the Rumeli Fortress. It was used during the Ottoman's second attempt to capture Istanbul. Having a 25m high central tower with five other watchtowers, the Fortress was turned into a military prison after the conquest of the city. As it was exposed to many restoration and renovation works, it no longer has its original view. Today, the Fortress serves an open air museum but only outer walls can be visited. You can walk over the road passing just through it.

Seven Tower Dungeons
The construction of the Dungeons started at the time of the Byzantine Emperor Theodosius II and four of them were completed during the Byzantine period. Sultan Mehmed the Conqueror added three more towers and from that time on it was called as Seven Tower Dungeons. First used to protect the treasury, they were turned into dungeons after the treasury was transferred to the Topkapı Palace. It was used as a prison until the beginning of 1800s and then turned into a shelter for the lions of Topkapı Palace first, and a gunpowder factory later on. Today, it serves as the largest “outdoor museum” of Istanbul and hosts open air concerts in the inner courtyard during summer months.
Beylerbeyi Palace
Built by Sultan Abdülaziz in 1865 as a summer residence of Ottoman sultans and a state guest house for the foreign heads of state, the Beylerbeyi Palace has a historical architecture attracting many people from all around the the world. Located along the Anatolian coast of the Bosphorus, the Palace was designed in the French neo-baroque style with a traditional Ottoman plan. Abdulhamid II was kept in captivity in this Palace from 1912 until his death in 1918 and today it serves as a museum.
Çırağan Palace

Maiden's Tower
Located off the shore of the Salacak district in Üsküdar, the Maiden’s Tower, also called as the Leander's Tower, has been used for a variety of purposes since its first construction. It is not known exactly when it was built; however, some sources suggest that it could be around 340 B.C. Sultan Mehmed the Conqueror pulled down the old tower and built a wooden tower in its place, which was destroyed due to a fire in 1719. Today’s tower was constructed in 1725 and since then, it was used as a lighthouse first and then a quarantine station during the cholera epidemic in 1830. There are several legends as to the origins of the tower, which are from Turkish, Greek and Byzantine cultures. Today, there is a restaurant serving inside the tower and it is a famous destination for local and foreign tourists. Private boats from Kabataş and Salacak make trips to the tower several times a day.
