Zanzibar has long been one of the most alluring destinations in the world. Just 35 km from mainland Africa, it has drawn traders from Asia, Europe and the Middle East to its palm-fringed shores for thousands of years. Merchants came to do business with each other and with the Omani sultans who ruled the islands for centuries. They sailed into her busy harbour bringing guns, pottery and cloth; they left bearing Africa's bounty: cloves, ivory and slaves. The business of buying and selling people flourished on the islands until it was abolished in 1873 (slave ownership remained legal until 1897). Zanzibar's architectural beauty - the unique Stone Town, the elegant whitewashed mansions - is the legacy of that infamous commerce, and many of the islanders are descendants of slaves.

After the last Sultan of Zanzibar was overthrown in a bloody coup in 1964, the islands united with the mainland state of Tanganyika to form the United Republic of Tanzania. The government began a long experiment with socialism, and for many years tourism was officially discouraged. But in recent years, the islands have been thrown open to visitors again. Travellers are making the journey to Zanzibar to bask in its hot sun and unhurried atmosphere, and to explore the coral reefs alive with exotic marine life. When they arrive, they soon discover Zanzibar's fascinating and distinct identity - the Swahili language and culture, the result of thousands of years of being the crossroads between Africa and the Islamic world. A good place to begin exploring this living history is Stone Town, the only major urban centre in the Zanzibar archipelago (which consists of the main island, Unguja, its sister island, Pemba, and numerous smaller islands). Stone Town is a maze of tall coral and limestone buildings packed onto narrow stone streets, shaded from the hot sun and often impassable to cars. Everything looks exotic in Stone Town, from the women shrouded in black to the elders in white robes sitting outside the mosques, and even the mangos and papayas crowding the shopkeeper's tables. The grand homes reflect the waves of African, Arabic, Indian and European influence in Stone Town

The grand homes of Stone Town - most of them built by wealthy merchants and landowners in the last century - reflect the waves of African, Arabic, Indian and European influence, as well as the neglect and decay of the past few decades. The intricately carved wooden doors and cool stone courtyards have fallen into disrepair, but some of the landmark buildings and larger homes recently have been renovated, many of them to accommodate tourists. One particularly successful restoration is Emerson's & Green Hotel, owned by Americans who have been on the island for many years. Every room is decorated in luxurious Swahili style with Arab and Indian antiques, and the beds are sprinkled with jasmine blossoms. The hotel's Rooftop Restaurant is a romantic spot for crab with coconut sauce, but beware, seating is on cushions on the floor, and reservations go quickly.

For a cheaper feast, Zanzibaris and tourists alike head to the evening market in a park on the waterfront. There's barbecued squid and shish kebabs, freshly-pressed sugar cane juice and local bread, all of it delicious but, as with street food anywhere, not for those with weak stomachs. Facing the park is the House of Wonders, a waterfront mansion built in 1883 by one of the sultans for state functions. Its name came from the many luxuries it introduced to the island, including massive chandeliers powered by the first electric generator in sub-Saharan Africa. Now closed and in a sorry state, it is slated to be restored and reopened as a museum of the island.

Next door is a building that has already undergone that transformation, the elegant, whitewashed Palace Museum. Formerly the primary residence for a succession of sultans, it now chronicles the years of Omani rule.

One room is devoted entirely to the saga of Princess Salme, a sultan's daughter who eloped with a German trader she met in Stone Town in the 1860s, never to live on Zanzibar again. She changed her name to Emily Ruete and years later wrote Memoirs of an Arabian Princess from Zanzibar. The book, a fascinating insider's look at life in a sultan's family, has been re-released and is available in shops in Stone Town. On the other side of Stone Town is the Anglican cathedral, built on the site of the former slave market immediately following abolition in 1873. British explorer David Livingstone made Zanzibar his base for many years, and was a leading light in the effort to eliminate the slave trade. The cathedral features a crucifix said to be made of wood taken from the tree in Zambia where Livingstone's heart was buried, and an altar built exactly where the slave whipping-post is believed to have been. More recently, a sculpture was installed on the cathedral grounds in memory of the thousands of slaves who passed through there. All of these landmarks can be visited on your own, or with one of the many guides operating on the island. You don't have to worry about finding them - they will find you. For a greater chance of getting a well-informed guide, ask to see the badge that shows they're licensed by the government. There are city tours, including the highlights of Stone Town and ruins on the outskirts of town, and spice tours, which cover the rural areas, including the plantations where cloves, cinnamon, cardamom and other spices are grown. Cloves replaced slaves as the islands' main export after abolition, and even today the air in town is often heavy with their sweet scent. If you're pressed for time, it is possible to combine a spice tour with the 90-minute drive to the east coast. This was the first area to be developed for tourists, although now hotels are spread out along the length of the island, and some even advertise on the Internet. Prices range from $20 per room in a very basic guest house, to $250 per person for a night in an all-inclusive, resort. For something in between, Matemwe Bungalows has earned a reputation for excellent service in a quiet setting that can only be described as casual luxury: just 16 thatched bungalows, with comfortable beds and simple, creative decor; no electricity (aside from solar-powered lights and water heaters) and no telephone; fresh seafood every day; and an experienced dive master. They'll arrange for a sailing trip with fishermen from the village next door, or simply leave you alone to watch the changing colours of the ocean from the comfort of the hammock on your very own veranda. Zanzibar and the surrounding islands have some of the best diving spots in the Indian Ocean, and there are several dive companies in town. The larger beach hotels offer diving and snorkeling packages; most small guest houses do not. It is on the coast that you truly feel the unhurried atmosphere of Zanzibar, and some visitors like to take their time, renting a moped to meander leisurely the length of the island. At the bottom and top of the island, fishermen take visitors out in motorized dhows to watch dolphins in the turquoise water.

The majority of Zanzibaris live a subsistence existence, surviving by fishing or trading, and increasingly by serving tourists. Until very recently, it was almost unheard of for a foreigner to be robbed or assaulted on Zanzibar. But with the growing number of affluent visitors, there have been more reports of such incidents, particularly in Stone Town at night.

Another distressing consequence of the new openness is that the town itself seems to have become, in a very short time, one giant billboard. Large, garish signs advertising everything from Coca-Cola to cigarettes have sprung up everywhere in the past few years. But many things haven't changed. The sun, the mellow mood, the constant shifting between past and present. Although some business people now tote cell phones, communications to and from Zanzibar are still unreliable and expensive. Even now, most of the beach hotels do not have telephones - which seems fitting, for when you step into another place and time, you should be blissfully beyond reach.