But contradiction is the city's defining characteristic: at dawn, while revellers head home from nightclubs and bars, others heed the call to prayer that rebounds from ancient minarets. Donkey carts vie with shiny BMWs in the noisy, narrow streets, and Oriental bazaars compete with Western boutiques for the custom of tourists and the 16 million residents.

To find your bearings, head for Galata Bridge, which crosses the Golden Horn: to the north of this strait is the new town, modern Beyoglu, and Taksim Square. To the south lies the old walled city, with the magnificent Hagia Sophia and Topkapi Palace at its heart.

TO DO AND SEE
Istanbul is a noisy and chaotic city. The Turks seem to take the mayhem in good spirit though, and so should you. The twisting, crowded old city streets exude an infectious energy. See the sights, dodge the cars, eat heartily. Like strong Turkish coffee, Istanbul can be gritty, but its rich flavour is bracing.

To get your bearings, head for the Galata Bridge, which spans the mouth of the Haliç (Golden Horn) inlet that separates Old Stamboul, also called Old Istanbul, from the 'new town', known as Beyoglu. Look to the north, and you will see modern Beyoglu and Taksim Square, from which high-rise hotels and smart shops radiate. To the south, across the Galata Bridge from the new town, lies the old walled city of Stamboul and Sultanahmet (after the sultan who built the Blue Mosque), with Hagia Sophia and Topkapi Palace at its heart. Stamboul isn't large, but it can be overwhelming, for it spans vast epochs of history and contains an incredible concentration of art and architecture. The best way to get around is on foot.

Until the early 1980s, Istanbul, with its crumbling ancient buildings, was its own best museum. Most artefacts of the city's past were locked away in storage or were poorly displayed in dusty, badly lit rooms. However, in recent years Istanbul's museums have been transformed. Topkapi Palace, which for 400 years was the palace of the Ottoman sultans, contains a glittering array of jewels, ceramics, miniature paintings and holy relics. The Archaeological Museum houses one of the most important collections of classical artefacts anywhere in the world. The Museum of Turkish and Islamic Arts holds superb examples of artistry and craftsmanship. The mosaics in the former church at Kariye are believed by many to be the finest surviving Byzantine artworks.

Another option is to explore the shores of the Bosphorus, the strait that divides Europe and Asia. The most pleasant way to do this is by ferry from the Eminönü docks in the old town. Along the way, you'll see wooded hills, villages large and small, modern and old-fashioned, and the old wooden summer homes, called yalis (waterside houses), that were built for the city's wealthier residents in the Ottoman era.

When looking at ferry schedules, remember that Rumeli refers to the European side, Anadolu to the Asian.

ATTRACTIONS

Anadolu Hisari

In 1393, Sultan Beyazit I built the Anatolian Castle, which is north of Istanbul on the Asian side of the Bosphorus, to cut off Constantinople's access to the Black Sea. The castle is a romantic sight, especially at sunset. Its golden stone blends into the surrounding forest, and tiny boats bob beneath its walls. An unmarked path leads up to the castle ruins.

Arkeoloji Müzesi

The Archaeology Museum houses a fine collection of Greek and Roman antiquities. There is a section for children, a special exhibition on Istanbul through the ages, and one on the different settlements at Troy. The admission fee also gains you entry to the nearby Eski Sark Eserleri Müzesi (Museum of the Ancient Orient) and Çinili Köskü (Tiled Pavilion). The Tiled Pavilion has ceramics from the early Seljuk and Ottoman Empires and tiles from Iznik, which produced perhaps the finest ceramics in the world during the 17th and 18th centuries. Covered in coloured tiles, the building is itself part of the exhibition.

Askeri Müze

In the north-western corner of Yildiz Park, the Military Museum contains a fascinating collection of military memorabilia from the 15th century to the present. In addition to costumes, flags and weapons, there are beautifully embroidered silk tents used by the Ottoman sultans on campaigns and personal artefacts belonging to Atatürk from the 1915 Gallipoli campaign.

Aya Sofya

The magnificent dome of Aya Sofya, more commonly known as Hagia Sophia (Church of Holy Wisdom), was the world's largest church from its completion in AD 537 until St Peter's Basilica was built in Rome 1000 years later. Perhaps the greatest work of Byzantine architecture, the cathedral was Christendom's most important church for 900 years. It was then converted into a mosque, and in 1936 it was made into a museum.

Blue Mosque

This massive structure, officially called Sultan Ahmet Camii (Mosque of Sultan Ahmet), is studded with mini- and semi-domes and surrounded by six minarets. Inside, it is decorated with 20,000 shimmering blue Iznik tiles interspersed with 260 stained-glass windows, and an airy arabesque pattern is painted on the ceiling. Before you enter the mosque, at the side entrance facing Aya Sofya, remove your shoes and leave them at the entrance. The Hünkar Kasri Carpet and Kilim Museums are in the stone-vaulted cellars of the Blue Mosque and upstairs at the end of a stone ramp.

Divan Edebiyati Müzesi

Also called the Galata Mevlevihane, the Divan Literature Museum contains costumes and memorabilia used by the Sufi mystics known in the West as the whirling dervishes. On the last Sunday of each month, dance performances and Sufi music concerts are held.

Dolmabahçe Sarayi

The last sultans of the Ottoman Empire resided at the Dolmabahçe Palace, erected in 1853. The palace is an extraordinary mixture of Hindu, Turkish and European styles of architecture and interior design. The structure was a symbol of Turkey's march away from its past and towards the European mainstream. The result was a riot of rococo: marble, vast mirrors, stately towers, and formal gardens along a facade stretching nearly a third of a mile. All gilt, crystal and silk, it is every bit as garish as Versailles.

Emirgan

This town on the European shore of the Bosphorus was named after a 17th-century Persian prince to whom Sultan Murat IV presented a palace here. The woods above are part of a park with flower gardens and a number of restored Ottoman pavilions. It's worth coming in late April just to see the tulips. The flowers were originally brought from Mongolia, and after their cultivation was refined by the Dutch, they became great favourites of the Ottoman sultans.

Eyüp Camii

The mosque complex of Eyüp on the Golden Horn is the holiest Islamic shrine in Turkey and attracts Muslim pilgrims from all over the world. Most of the building was completed in the 15th century by Sultan Mehmet the Conqueror. Despite the numbers of pilgrims, particularly at Friday midday prayer, the tree-shaded courtyards and fluttering pigeons imbue it with a sense of peace not found anywhere else in this often frenetic city. The tomb itself is small and covered with brightly decorated ceramic tiles. Non-Muslims are welcome to join the hushed pilgrims who pray at the tomb, but should remember to remove their shoes beforehand.

Galata Kulesi

From when the Genoese built the Galata Tower in 1349 until 1960, the rocket-shaped tower served as a fire lookout. Today it houses a restaurant and nightclub and a viewing tower (accessible by elevator, and open during the day). In 1492, when the Spanish Inquisition drove Sephardic Jews from Spain and Portugal, many refugees settled here. For centuries after, a large Jewish population lived in Galata. Today, 16 active synagogues serve a Jewish community of 25,000.

Galatasaray Meydani

Galatasaray Square is in the heart of the Beyoglu district. The impressive building behind the iron gates on the square is a high school, established in 1868 and for a time the most prestigious in the Ottoman Empire. Across Istiklal Caddesi, at Number 51, is the entrance to the Çiçek Pasaji, the Flower Arcade, with flower stalls, restaurants, bars and street entertainment. Behind that is the Balik Pazari, the Fish Market, a bustling labyrinth of stands peddling fish, fruits, vegetables and spices. Open Monday to Saturday during daylight hours. At the end of the market, at Mesrutiyet Caddesi, is the Üç Horan Armenian Church.

Grand Bazaar

The Grand Bazaar is a maze of 65 winding, covered streets crammed with 4000 tiny shops, cafes and restaurants. Originally built in the 1450s, then ravaged by fire and rebuilt, it is filled with thousands of items: fabric, clothing, brass candelabra, furniture and jewellery. A separate section for antiques at the centre of the bazaar, called the bedestan, is worth visiting. Outside the western gate to the bazaar, through a doorway, is the Sahaflar Çarsisi, the Old Book Bazaar, where you can buy both new editions and antique volumes in Turkish and other languages. As always, the best prices are those you get when the salesman thinks you are about to leave.

Hippodrome

Once a Byzantine stadium with seating for 100,000, the Hippodrome was the centre for public entertainment such as chariot races and circuses. Disputes between rival groups of supporters of chariot teams often degenerated into violence. Thirty thousand people died here in what came to be known as the Nike riots of AD 531. The original shape of the Hippodrome is still clearly visible. The monuments that can be seen today on the open space opposite the Blue Mosque are the Egyptian Obelisk (Dikilitas), the Column of Constantinos (Örme Sütün) and the Serpentine Column (Yilanli Sütun), taken from the Temple of Apollo at Delphi in Greece; all these formed part of the central barrier around which the chariots raced.

Ibrahim Pasa Sarayi

The palace of the son-in-law and grand vizier of Süleyman the Magnificent was built about 1524. The striated stone mansion was furnished to be the finest private residence in Istanbul, but Ibrahim Pasha didn't have long to enjoy it: he was executed when he became too powerful for the liking of Süleyman's power-crazed wife, Roxelana. The palace now houses the Museum of Turkish and Islamic Arts, where you can learn about the lifestyles of Turks at every level of society, from the 8th century to the present.

Kariye Müzesi

Often passed over because of its inconvenient location at Istanbul's western edge, the Kariye Museum occupies what was once the Church of the Holy Saviour in Chora, erected in the 5th century and rebuilt several times since. The main attraction is the dazzling 14th-century mosaics and frescoes, considered to be among the finest Byzantine works in the world. The historic Ottoman buildings around the museum have also been restored. West of the Chora are the Constantinian Walls, built by Emperor Theodosius II in AD 413. Several stories high and from 10 to 20 feet thick in spots, the walls protected Constantinople from numerous onslaughts and were breached only twice: by the crusaders in the 1200s and by Mehmet the Conqueror in 1453.

Mozaik Müzesi

Tucked away behind the Blue Mosque, the often-overlooked Mosaic Museum is actually the ruins of the Great Palace of Byzantium, the imperial residence of the Byzantine emperors when they ruled from Iran to Italy. The mosaics that give the museum its name lay hidden beneath the earth for 1000 years before being uncovered by archaeologists in 1935.

Princes' Islands

In the days when Istanbul was known as Constantinople, religious undesirables sought refuge in these nine islands in the Sea of Marmara. By 1900, businessmen had built many of the Victorian gingerbread-style houses that lend the islands their charm. Today the islands provide a leafy retreat from Istanbul. Transport is by horse-drawn carriage or bicycle. Only the two largest islands, Büyükada and Heybeli, are of real interest. Büyükada has a public beach, Victorian houses and the Greek Monastery of St George, a popular pilgrimage site at Greek Easter. In Heybeli, there are tea houses and cafes by the dock, small sandy beaches, and the ruined monastery of Panaghia, founded in the 15th century.

Sadberk Hanim Müzesi

An old waterfront mansion houses the Sadberk Hanim Museum, named for the deceased wife of the late billionaire businessman Vehbi Koç. Though small, it houses an enviable collection of top-quality pieces. Half the museum is dedicated to Islamic and Turkish arts (from Iznik tiles to Ottoman embroidery and calligraphy) and half to Anatolian archaeology.

Sokollu Mehmet Pasa Cami

The small Mosque of Mehmet Pasa, built in 1571, is generally regarded as one of the most beautifully realised projects of the master architect Sinan, who designed more than 350 other buildings and monuments under the direction of Süleyman the Magnificent. Rather than dazzle with size, he integrated all the parts into a harmonious whole, from the courtyard and porticoes outside, to the delicately carved mimber (pulpit) and well-preserved Iznik tiles set off by white walls and floral-motif stained-glass windows inside.

Stefi Stefan Bulgar Kilisesi

The neo-Gothic Bulgarian Church of St Stefan is one of the most remarkable structures in Istanbul. Both the exterior and all the interior decor are made entirely of cast iron. The church was prefabricated in Vienna, shipped down the Danube and erected on the western shore of the Golden Horn in 1871 by the then-flourishing Bulgarian Orthodox community in Istanbul. Despite the dwindling numbers of the Bulgarian community, the church has been recently restored and repainted and is set in neatly tended gardens.

Topkapi Sarayi

The vast Topkapi Palace was the residence of sultans and their harems until 1868. Sultan Mehmet II built the palace in the 1450s. Over the centuries, it acquired four courtyards and quarters for some 5000 full-time residents. One of the most popular sections is the Harem, a maze of 400 halls, terraces and other rooms. There are also rooms filled with jewels, Turkish and Persian miniatures, mosques, fountains and reflecting pools scattered amid gardens.

Yerebatan Sarnici

Also known as the Basilica Cistern or the Sunken Cistern, Yerebatan Sarnici is the most impressive part of an underground network of waterways. It is said to have been created at the behest of Emperor Constantine in the 4th century and expanded by Justinian in the 6th century, and indeed most of the present structure dates from the Justinian era. The cistern was always kept full as a precaution against long sieges. It is still an atmospheric space, with 336 marble columns rising 26 feet to support Byzantine arches and domes. Piped-in classical music accompanies the sound of endlessly dripping water.