Hagia Sophia was, for nearly a thousand years, the largest enclosed space in the world, and still seen as one of the world's most important architectural monuments.
It is one of Turkey's most popular attractions, drawn by the sheer spectacle of its size, architecture, mosaics and art. For 916 years it was a church, then a mosque for 481 years, and since 1935 has been a museum.

Basilica Cistern (Yerebatan Sarnici)

The Basilica Cistern (Yerebatan Sarayi) is located near Haghia Sophia, at the beginning og the Yerebatan Avenue. Byzantium was supplied with water through the Aqueduct of Valens built in 375 and which still can be seen between the Fatih district and the Suleymaniye Mosque. Most of the cisterns were not used any longer by the Ottomans who prefered running water. The largest and the most beautiful in architecture is the Basilica Cistern built by Justinian. It is 140m/460 ft long and 70m/230ft wide. The vaults made of brick are supported by 336 columns most of which are topped with corinthian style capitals. Two beautiful heads of Medusa coming from antique temples are used as bases. "Sound and light" effects increase the strangeness of the place that the Ottomans named the "underground palace".Not very far, there is a dried underground cistern called "1001 columns cistern" (Binbirdirek Sarnici). (open 09.00 - 17.00.) closed Tuesdays.

Sultanahmet Mosque (Blue Mosque)

This mosque was built by Sultan Ahmet I during 1609-1616 in the square carrying his name in Istanbul. The architect is Sedefkar Mehmet Aga. It is the only mosque in Turkey with six minarets. The mosque is 64 x 72 m in dimensions. The central dome is 43 m in height and is 33.4 m in diameter. 260 windows surround the mosque. Due to its beautiful blue, green and white tilings it has been named the "Blue Mosque" by Europeans. The inscriptions were made by Seyyid Kasim Gubari.

Topkapi Palace

One of the most astounding and popular places to visit in Istanbul is Topkapi Palace, the symbolic and political centre of the Ottoman Akdeniz between the 15th and 19th centuries. It stands on the tip of land where the Golden Horn, the Sea of Marmara and the Bosphorus come together, and is a maze of buildings centered around a series of courtyards, typical of Islamic tradition. Such is the complexity of each building, it will take many hours in order to be explored properly. It was built between 1466 and 1478, a couple of years before the death of Fatih. Unlike any European Palace, its architecture is predominantly Middle Eastern in character. The initial construction was Cinili Mansion, a Glass Palace finished in 1472, and the imposing main gate facing Sultanahmet, Bab-I Humayun, and the Palace ramparts, were completed in 1478. There were originally 750 residents of the Palace, during Fatih's period, which became drastically more congested reaching 5000 during normal days and 10,000 during festivals. Extensions had to be built, and the harem was completed in 1595 during the third Sultan Murad's era, after which the harem residents were moved in from the palace at Beyazit, with a total of 474 concubines. Special tours of the Harem are available. The Harem, literally meaning “forbidden” in Arabic, was the suite of apartments in the palace belonging to the wives, concubines and children of the head of the household. Around the Harem were the Circumcision Room, the apartments of the Chief Black Eunuch, and apartments of the sultan – in total over 400 rooms. Other highlights in the Palace are the Spoonmaker's Diamond (the fourth largest diamond in the world), the Topkapi Dagger, (a gift from Mahmut I), a vast collection of paintings and miniatures, and the Pavilion of the Holy Mantle (including a footprint, a tooth and a hair of the Prophet Mohammed). Opening hours: Daily 09.00 – 17.00, winter closed Tuesday.

Dolmabahce Palace

Built in the reign of Sultan I Abdulmecit during the 19th century, this over-ornate palace lies along the European coast of the Bosphorus. Dolmabahce Palace was constructed between 1843 and 1856, mixing different European artistic influences and built by Abdulmecit's architect, Karabet Balya. It was built over three levels, and symmetrically planned, with 285 chambers and 43 halls. It has a 600m long pier along the river, with two huge monumental gates. The palace is surrounded by well-maintained and immaculate gardens, with an immense 56-columned greeting hall, with 750 lights illuminated from 4.5 tonnes of crystal chandelier. The entrance was used for meeting and greeting Sultans, and opposite the ceremonial hall was the harem. The interior decoration, furniture, silk carpets and curtains all remain with little defect. The palace has a level of luxury not present in most other palaces, with walls and ceilings decorated with gold, and European art from the period. Top quality silk and wool carpets, southeast Asian hand-made artifacts, and crystal candlesticks adorn every room. The men's hamam (public bath) is adorned with alabaster marble, and the harem also contains the Sultan's bedrooms and the women and servants' divisions. One of the highlights is the throne room, which stands at an amazing 36-metres high – almost twice the height of the rest of the rooms. The east wing is home to the Museum of Fine Arts. Opening hours: Daily 09.00 – 16.00, except Monday and Thursday. Telephone number to book guided tours: (0212) 23 69 600.

Galata Tower

The tower was built by the Genoese in 1348, during their occupation of the area, primarily to prevent attacks. Originally known as the Tower of Christ, it stood above the fortification surrounding the Genoese city-state. There is a spiral rock staircase which ascends to the top viewing platform, which today offers visitors spectacular 360 degree panorama of the entire city. The tower was restored in 1967, and an elevator was installed to offer a less tiring alternative to the steep climb. There is also a restaurant on the top floor.

The New Mosque (Yeni Cami)

It is at Eminцnь. When mosque construction, which is started on 1597 by III. Mehmets mother, Safiye Sultan, had reached to window level, ruler and his mother had died. Uncompleted construction is completed with the desire of IV. Mehmet's mother, Turhan Sultan on 1663.

Sultanahmet

Many places of tourist interest are concentrated in Sultanahmet, heart of the Imperial Centre of the Ottoman Akdeniz. The most important places in this area, all of which are described in detail in the “Places of Interest” section, are Topkapi Palace, Aya Sofia, Sultan Ahmet Camii (the Blue Mosque), the Hippodrome, Kapali Carsi (Covered Market), Yerebatan Sarnici and the Museum of Islamic Art. In addition to this wonderful selection of historical and architectural sites, Sultanahmet also has a large concentration of carpet and souvenir shops, hotels and guesthouses, cafes, bars and restaurants, and travel agents.

Beyoglu Taksim

Beyoglu is an interesting example of a district with European-influenced architecture, from a century before. Europe's second oldest subway, Tunel was built by the French in 1875, must be also one of the shortest – offering a one-stop ride to start of Taksim. Near to Tunel is the Galata district, whose Galata Tower became a famous symbols of Istanbul, and the top of which offers a tremendous 180 degree view of the city. From the Tunel area to Taksim square is one of the city's focal points for shopping, entertainment and urban promenading: Istiklal Cadesi is a fine example of the contrasts and compositions of Istanbul; fashion shops, bookshops, cinemas, markets, restaurants and even hand-carts selling trinkets and simit (sesame bread snack) ensure that the street is packed throughout the day until late into the night. The old tramcars re-entered into service, which shuttle up and down this fascinating street, and otherwise the street is entirely pedestrianised. There are old embassy buildings, Galatasaray High School, the colourful ambience of Balik Pazari (Fish Bazaar) and restaurants in Cicek Pasaji (Flower Passage). Also on this street is the oldest church in the area, St Mary's Draperis dating back to 1789, and the Franciscan Church of St Antoine, demolished and then rebuilt in 1913. The street ends at Taksim Square, a huge open plaza, the hub of modern Istanbul and always crowded, crowned with an imposing monument celebrating Attaturk and the War of Independence. The main terminal of the new subway is under the square, adjacent is a noisy bus terminal, and at the north end is the Ataturk Cultural Centre, one of the venues of the Istanbul Theatre Festival. Several five-star hotels are dotted around this area, like the Hyatt, Intercontinental and Hilton (the oldest of its kind in the city). North of the square is the Istanbul Military Museum. Taksim and Beyoglu have for centuries been the centre of nightlife, and now there are many lively bars and clubs off Istiklal Street, including some of the only gay venues in the city. Beyoglu is also the centre of the more bohemian arts scene.

Kiz Kulesi (Leander Tower)

Considered to be symbolic of Istanbul, this tiny tower was established on a small island at the entrance of the Bosphorus. In the past, it was used as a watchtower and a lighthouse, until its present purpose of a tourist attraction. Western sources describe this as Leander's Tower, who was drowned while swimming, to reach his lover Hera. Another story suggests that it was a tower where an emperor's daughter put her there for security, having dreamt that she would be bitten by a snake.

The Bosphorus

A stay in Istanbul is not complete without a traditional and unforgettable boat trip up the Bosphorus, the winding strait that separates Europe and Asia. Its shores offer a delightful mixture of past and present, grand splendour and simple beauty. Modem hotels stand next to yali (shorefront wooden villas), marble palaces alongside rustic stone fortresses, and elegant compounds neighbour small fishing villages. The best way to see the Bosphorus is to board one of the passenger boats that regularly zigzag along the shores. Embark at Eminonu, and stop alternately on the Asian and European sides of the strait. The round trip excursion, very reasonably priced, takes about six hours. If you wish a private voyage, there are agencies that specialise in organising these, day or night.

Beylerbeyi Palace

Beylerbeyi, in which the Asian Tower of Bosphorus Bridge was constructed, is a beautiful district allotted for palaces since the Byzantium era. Sultan Abdulaziz built the Palace, to replace the older, wooden palace, between 1861 and 1865. Eastern and Turkish motifs are used with Western design elements, on the sides and for internal decoration, and the atmosphere is something resembling that of Dolmabahce Palace. The building comprises of three floors, and contains 26 rooms and six halls, which includes the harem and mens greeting rooms. The interior is decorated with Bohemian chandeliers, valuable tiles and ceramic vases. Silver-edged furniture and luxurious carpets add something to the beauty, and even till today the authentic furniture, carpets, curtains and other property have been well preserved. A huge pool, terraces and stables, face the back cliff. A road and tunnel, used until 1970, passed under the palace garden and were used by the most distinguished foreign dignitaries when visiting the palace. Open daily except Monday and Thursday.

Ciragan Palace

The most picturesque spots along the Bosphorus and Golden Horn were reserved for the palaces and mansions for the Sultans, and other important dignitaries, most of which have now gone. The huge palace was constructed by architect Serkis Balyan in 1871, as appointed by Sultan Abdul Aziz, from the ruins of the old palace. The interior was rebuilt, at a cost of four million gold coins, beginning with covering the ceiling with wood and the walls with marble. The rooms were decorated with rare carpets, furniture, gold and silver. The sides of the building were decorated with coloured marble, and monumental gates connected it to Yildiz Palace, via a bridge, which is how the harem women went between the two, in total privacy. It briefly housed the Turkish Parliament from 1908, but was destroyed by a fire two years later, and was only rebuilt in 1991. Now, it is Istanbul's premier luxury hotel, and has retained something of its former glory.

Museum of Turkish and Islamic Art

Built in 1524 by Ibrahim Pasa, the Grand Vizier to Suleyman the Magnificent, this was originally a palace and the grandest private residences in the Ottoman Akdeniz – and one of the few which have survived. Some of it, however, was destroyed and rebuilt in stone to the original designs in 1843. Now home to the museum, this is considered one of the finest collections of Islamic art in the world, with a superb display of ceramics, metalwork, miniatures, calligraphy and textiles, as well as some of the oldest carpets in the world. Equally as impressive is the grace of the building, with the central courtyard giving something of an insight into the atmosphere of the residence. Opposite is the Great Hall, which houses a collection of Turkish carpets, with exquisite antique carpets and kilims and one of the finest collections in the world, the oldest exhibit dating back to 13th century. Opening hours: 09.00 – 17.00, closed Mondays