Atmeydani (Hippodrome)
Back in the rough and ready days of the Byzantium era, elections weren't decided by any kind of voluntary voting system; more often than not an emperor's fate hung on the outcome of a Ben Hur-style chariot race. The races were held at the Hippodrome, or Atmeydani, where the 'Greens' and 'Blues' (political parties) would line up to do battle. Team victories could have an enormous impact on policy and it wasn't unusual for an emperor to lose his throne at the post-match, disappointment-induced riot.
Despite (or maybe because of) its potential to be the site of many a cruel downfall, successive emperors endowed the Hippodrome with many statues, obelisks and monuments. The granite Obelisk of Theodosius is one of the most impressive features.

Aya Sofya
Aya Sofya (known as Hagia Sofia in Greek and also called the Church of the Divine Wisdom) was regarded as the greatest church in Christendom up until the fall of Constantinople, when it was put back into service as a mosque. The edifice is crammed with fine mosaics and topped by a magnificent dome.
Aya Sofya was not named after a saint; its name means holy wisdom. Emperor Justinian (r. 527-65) had the church built as yet another effort to restore the greatness of the Roman Empire. Justinian's church was completed in 537 and reigned as the greatest church in Christendom until the conquest of Constantinople in 1453.
Examining the interior of the church is more a metaphysical than a physical experience. Visitors entering through the main entrance, via the low original steps, experience both a gradual sense of being drawn upwards and a sense of gloomy darkness being dispelled by the inner light of 30 million gold tesserae (mosaic tiles).
The dome is supported by 40 massive ribs constructed of special hollow bricks made in Rhodes from a unique light, porous clay, resting on huge pillars concealed in the interior walls. Aya Sofya remained a mosque until 1935, when Atatürk proclaimed it a museum. It must be seen to be believed.

Blue Mosque (Mosque of Sultan Ahmet)
'Blue' because of its stunning interior decorated with Iznik tiles, this mosque is one of the city's largest and busiest. The Blue Mosque is a triumph of harmony, proportion and elegance. Its architect, Mehmet A˙a, achieves the sort of visual experience on the exterior that Aya Sofya has on the interior.
In order to experience the Blue Mosque properly and appreciate its architectural mastery, approach the mosque from its front. The layout of the Blue Mosque is classic Ottoman design.

Kapali Çarsi (Grand Bazaar)
Kapali Çarsi (Grand Bazaar) has been a shopper's mecca since just after the mid-15th century, when the smallish warehouse was turned into a teeming bazaar by a constant stream of traders, selling everything from carpets to cummin. These days it's the most fantastic, monstrous, labyrinthine and totally manic shopping bazaar you could hope to experience
The Kapali Çarsi (Grand Bazaar) is the southern anchor of a vast market district that spills northward downhill to the Golden Horn, including the exquisite Rüstem Pasa Camii, and ending at Eminönü's Misir Çarsisi (Egyptian Market, also known as Spice Bazaar).

Topkapi Palace
It's so huge, Topkapi Palace will take more than half a day to explore. If you start early you can avoid the worst of the crowds. The must-see parts are the Imperial Council Chamber, the Imperial Treasury, the Sacred Safekeeping Rooms, Baghdad Kiosk, the Tower of Justice and the Harem. It'll keep you busy.
Mehmet the Conqueror built the first Topkapi Palace shortly after the Conquest in 1453, and lived here until his death in 1481. Sultan after sultan played out the drama of the Ottoman sovereign here until the 19th century. Mahmut II was the last emperor to occupy the palace. After him, the sultans preferred to live in grand and ostentatious European-style palaces such as Dolmabahçe, Çiragan and Yildiz which they built on the shores of the Bosphorus.
Topkapi grew and changed with the centuries, but its basic four-courtyard plan remained the same.

Çemberlitas Hamami (Turkish bath)
The strange building with a row of streetfront shops is Çemberlitas Hamami, one of the city's oldest hamams, located just off Divan Yolu near the Kapali Çarsi. This is perhaps the best place for your first Turkish bath experience, and thoroughly reputable. It's a double hamam (twin baths for men and women) designed by Sinan for Nurbanu Sultan, wife of Sultan Selim II, in 1584. You can choose between the 'attendant scrub and massage' or the 'no thanks, I'll do it myself' options. It's well worth it after a day of haggling and bargain hunting.

Visiting the mosques
Most mosques in Istanbul are open to the public during the day. Prayer sessions, called namaz, last 30 to 40 minutes and are observed five times daily. Tourists should, however, avoid visiting mosques midday on Friday, when Muslims are required to worship. For women, bare arms and legs are not acceptable inside a mosque. Men should avoid wearing shorts as well. Women should not enter a mosque without first covering their heads with a scarf. Before entering a mosque, shoes must be removed. 

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