Merida (Yucatan state) Merida was founded in 1542 on the site of an ancient Mayan city. Residents speak both Spanish and Mayan.

During the 19th century, Merida flourished, thanks to its valuable hemp exports. The city enjoyed an influx of European luxuries and, today, remains full of visible legacies and lavishly decorated homes from that prosperous time.

Called "The Paris of the Western World," Merida exudes a distinctly European air. Horse-drawn calesas cruise the streets and take visitors on tours of the city. Paseo Montejo, a boulevard built at the turn of the 20th century, leads past splendid mansions, which range from Moorish to rococo in style. (During World War I, Merida claimed more millionaires per capita than any other city in the world.) An incentive trip to Merida can be combined with a segment in Cancun.

Oaxaca (Oaxaca state) Considered the most colonial city in Mexico, Oaxaca was founded by Hernan Cortes in 1529. It sits in a valley surrounded by the towering Sierra Madre del Sur. Built in the shadow of the ruins of the Mixtec and Zapotec civilizations, it is a stunning mixture of colonial and Indian influence.

Many of Oaxaca's buildings are constructed of an unusual greenish volcanic stone that takes on a golden tone at sunset. Others are painted bright turquoise or pink. Bougainvillea and roses tumble over the walls, and geraniums spill out of huge clay pots. Completing this colorful palette is the azure blue sky over the valley.

Oaxaca and the surrounding villages are rich with architectural styles from the past. The streets are filled with churches and other colonial-era structures that are ornate and splendid. Except for the presence of cars, the atmosphere is reminiscent of a bygone era. An incentive trip to Oaxaca can be combined with a trip to the Bays of Huatulco.

Puebla (Puebla state) Puebla lies in a large valley flanked by four volcanoes: Popocatepetl, Iztaccohuatl, Malinche, and Citlaltepetl. The city was established in 1531 by colonists to whom Spain had granted lands and Indian slaves.

Noted for its French Renaissance design, Puebla's colonial architecture features many churches and buildings with ornamental, wrought-iron balconies and window gratings. Throughout the city, walls are adorned with a lavish combination of dark red and vivid Talavera tiles. (This colorful form of decorative art was originally introduced by tilemakers from Toledo, Spain.)

Convention Crowd * Place: Cancun

* Company: American Chemical Society

* Attendees: 4,000

* Hotels: Camino Real, Krystal, Hyatt Regency, Fiesta Americana Cancun & Coral Beach, Presidente Inter-Continental, Continental Plaza

Christine Pruitt, in charge of conventions for the American Chemical Society in Washington, D.C., used Travel Planners, Inc., San Antonio, Texas, to smooth the way for the 4,000 attendees of the 5th Chemical Congress of North America.

"Cancun worked well for this meeting because the major hotels were so close to the convention center. The local bus that runs on the main thoroughfare was so reliable, I saved $30,000 off my budget because I didn't have to use special shuttle buses. Also, the Cancun Convention Center is extremely well-designed and that added to the overall success as well."