There's little to see in downtown Cancun; most visitors head straight for the zona hotelera and the beaches. Though you're free to go anywhere, some of the hotels do their best to make you feel like a trespasser, and staff will certainly move you off the beach furniture if you're not a guest. To avoid being eyed suspiciously by hotel heavies, head for one of the dozen or so public beaches: all are free but you may have to pay a small charge for showers. Entertainment and expensive watersports are laid on all around the big hotels; if you venture farther, where more sites await construction, you can find surprisingly empty sand and often a small group of nude sunbathers.

To catch a bit of culture while you're out here, the Sheraton boasts a small Maya ruin in its grounds, above the pool, while the Museo de Antropologia, located behind the convention center (Tues-Fri 9 a.m.-7 p.m., Sat & Sun 10 a.m.-5 p.m.; $3, free on Sun), has a small but absorbing outline of Mesoamerican and Maya culture and history, with information in English and Spanish. Cancun's largest Maya remains, the Ruinas del Rey (daily 8 a.m.-5 p.m.; $3, free on Sun), are at Km 17, overlooking the Nichupt6 Lagoon. They're not especially impressive - and, if you decide not to take one of the guides at the entrance, there's no information available to explain them - but the area is peaceful and very good for bird - and iguana - watching.

The best snorkeling in Cancun is at Punta Nizuc, next to Club Med territory. You aren't allowed to cross the grounds unless you're staying there, so you have to get off the bus at the Westin Regina Resort, cross their grounds to the beach, then turn right and walk for about twenty minutes until you reach the rocky point. Walk across the rocks and snorkel to your heart's content. To join a snorkeling tour or go diving, contact Aqua Tours (98/83-04-33) or Fortunal (98/86-13-98 or 85-13-96). Rates range from a one tank dive at about $45 to a full PADI open water certification course, which costs around $375. To view the colorful underwater life in a more leisurely fashion, take a trip on Nautibus (98/83-35-52 or 83-21-19; $25), a glass-bottomed boat that leaves from Playa Linda every ninety minutes from 8 a.m. until 3:30 p.m.

Hand-picked by computer, Cancun is, if nothing else, proof of the rise and rise of Quintana Roo, and of Mexico's remarkable ability to get things done in a hurry if the political will is there. In 1970 there was nothing here but an island sand-spit and a fishing village of some 120 people. Now it's a city with a resident population of half a million and with almost two million visitors a year. To some extent the computer selected its location well. Cancun is marginally closer to Miami than it is to Mexico, and if you come on an all-in package tour the place has a lot to offer: striking modern hotels on white beaches; high-class entertainment from golf to scuba-diving; and much of the rest of the Yucatan is easily accessible. For the independent traveler, though, it is expensive, and can be frustrating and unwelcoming. You may well be forced to spend the night here, but without pots of money the true pleasures of the place will elude you. There are, in effect, two quite separate parts to Cancun: the zona commercial downtown - the shopping and residential center which, as it gets older, is becoming genuinely earthy - and the zona hotelera, a string of hotels and tourist amenities around "Cancun island," actually a narrow strip of sandy land connected to the mainland at each end by causeways. It encloses a huge lagoon, so there's water on both sides.

The post office is on Av. Sunyaxchen at the junction with Xel-Ha (Mon-Fri 8 a.m.-7 p.m., Sat 9 a.m.-l p.m.). Service is efficient and friendly and there's a reliable Lista de Correos (postcode 77501). All the main banks - many with 24-hour ATMs - are along Tulum and in the zona hotelera; banking hours are 9 a.m. to 1:30 p.m. but foreign exchange has to be done between 10 a.m. and 1 p.m. Banco del Atlantico, Tulum 15, offers good rates and credit card advances over the counter. There's another branch, with a money exchange booth (Mon-Fri 11 a.m.-2 p.m. & 4-9 p.m.), in the zona hotelera on the corner of the convention center at Km 9. Banamex, Tulum 19, and in Plaza Terramar in the zona hotelera, offers a bad exchange rate but has a convenient ATM, as does Bancomer, Tulum 26. The many casas de cambios will change cash (including currencies other than US$) and travellers's cheques faster than the banks, but at worse rates.

Many hotels arrange trips to the chief Maya ruins - most commonly Chichen Itza, Tulum and Coba - check with the receptionist about the latest offers. Downtown street names in Cancun are often followed by the letters SM and two numbers. These stand for Supermanzanas, or city districts, usually bounded by major thoroughfares. They're shown on all the city maps and do help you to find your way around.

Listings:
American Express Tulum 208, next to Hotel America (98/84-19-99; fax 84-69-42).

Consulates
Canada, Plaza Mexico 312, Av. Tulum (Mon-Fri 10 a.m.-2 p.m.; 98/84-37-16); Germany, Punta Conoco 36, 5M24 (Mon-Fri 10 a.m.-l p.m.; 98/84-18-98); Italy, La Mansi6n Costa Blanca Shopping Centre (Mon-Fri 9 a.m.-2 p.m.; 98/83-21-84); Sweden, Yaxchila'n 71, 5M25 (Mon-Fri 9 a.m.-2 p.m.; and fax 98/84-80-48); UK, The Royal Caribbean, zona hotelera (Mon-Fri 9 a.m.-5 p.m.; 98/85-11-66, ext. 462); United States, Edificio Marruecos 31, Av. Nader 40 (Mon-Fri 9 a.m.-2 p.m. & 3-5:30 p.m.; 98/84-24-Il or 84-63-99; fax 84-82-22).

Laundry
Lavender(a Las Palapas, on Gladiolas at the far side of the park (Mon-Sat 7 a.m.-8 p.m., Sun 8 a.m.-2 p.m.); Lavenderia Alborada, Av. Nader, just south of City Hall.