The medina of Fès el-Bari (Old Fès) is the largest living medieval city in the world. Its incredible maze of 9400 twisting alleys, blind turns and souqs are crammed with shops, restaurants, workshops, mosques, medersas (theological colleges), dye pits and tanneries. A riot of sights, sounds and smells, 21st-century Fès is groaning at its 9th-century seams.

Despite its designation as a World Heritage site, investment has been slow to follow. While the chic cafe-lined boulevards of the ville nouvelle provide a stark contrast, many young Fassis remain jobless, and the bright lights disguise the sad lot of the poorer people living on the periphery.

For the short-term visitor, Fès is terribly exotic and can be difficult to come to grips with. The medina can seem totally impenetrable. Though the amount of hassle is far less than it once was, the attention of unofficial guides, small boys, touts and shopkeepers can be intimidating for some. It is a veiled, self-contained city where life moves to centuries-old traditions - a city that doesn't easily bare its soul. With time, visitors begin to glimpse behind the anonymous walls and appreciate the rich culture and spirituality that is Fès.

Aït Benhaddou is one of the most exotic and best-preserved kasbahs in the entire Atlas region. This is hardly surprising, since it has had money poured into it as a result of being used for scenes in as many as 20 films. In recent years its population has dwindled, but it is under Unesco protection.

This huge square is the backdrop for one of the world's greatest spectacles. Lively at any hour of day, Djemaa el-Fna comes into its own at dusk when the curtain goes up on rows of open-air food stalls infusing the area with mouthwatering aromas. Jugglers, storytellers, snake charmers, musicians and acrobats fill the remaining space.

In between the groups of spectators, diners, shoppers and tourists weave the occasional hustler, pickpocket, knick-knack seller, hashish dealer and glue-sniffing kid. On the outer edges are the juice stalls with their kerosene lanterns ablaze. Beyond them, hunched on the ground with their eye-catching wares spread before them, herbalists sit poised to prescribe a potion for whatever ails you.

Later at night, with fewer visitors around, musicians from the Derkaoua and Gnawa spiritual brotherhoods start playing their strong hypnotic music on drums, flutes and ginbris (two- or three-string guitars).

The crowning achievement of King Hassan II, this phenomenal building is the world's third-largest mosque. It was built to commemorate the former king's 60th birthday and rises above the ocean on a rocky outcrop reclaimed from the sea. It's a vast building that can hold 25,000 worshippers and accommodate a further 80,000 in its courtyards.

Designed by French architect Michel Pinseau, the mosque is topped by a soaring 210m (689ft)minaret, which shines a laser beam towards Mecca by night. In addition to this high-tech call to prayer, the mosque also has a centrally heated floor, electric doors, a retractable roof and a section of glass flooring allowing the faithful to see the Atlantic washing the rocks below.

Above all though, it is the vast size and elaborate decoration of the prayer hall that is most striking. Large enough to house Paris' Notre Dame or Rome's St Peter's, it is blanketed in astonishing woodcarving, zellij (tile work) and stucco moulding.

The project cost more than half a billion dollars and was paid for largely by public subscription. Although most Moroccans, particularly those from Casablanca, are very proud of their modern monument others believe this vast sum might have been better spent. In particular, resentment lingers among the slum dwellers who were evicted without compensation from the area around the mosque.

Volubilis is the site of the largest and best-preserved Roman ruins in Morocco. Dating largely from the 2nd and 3rd centuries AD, excavations have revealed that the site was originally settled by Carthaginian traders even earlier. At its peak, it is estimated that the city housed up to 20,000 people. Take a guide, a hat and plenty of water. Magical at dusk.