Campeche is one of the best-preserved colonial cities in Mexico — a walled port where brightly painted mansions and cobblestone streets have barely changed since Spanish pirates made this place their favourite target. The historic centre was declared a UNESCO World Heritage Site in 1999, and unlike some heritage designations, this one actually shows: the overhead cables are gone, the facades are immaculate, and the atmosphere is genuinely lovely.
The city is the capital of the state of the same name, which stretches south into the jungle toward Guatemala. Within the state you'll find some of the most impressive and least-visited Maya ruins in Mexico. Edzna is close and easily done as a half-day trip; Calakmul, deep in the biosphere reserve, is a full expedition — remote, magnificent, and often nearly empty.
The seafood here is exceptional. The Gulf of Mexico laps at the city's doorstep, and the waterfront malecón — a wide modern promenade — is the place to stroll at sunset. Don't leave without eating at La Pigua, the classic spot for shrimp, crab, and pan de cazón (a layered tortilla dish with dogfish that is very much the local speciality). The forts ringing the city, built in the 17th century to defend against pirate raids, are worth visiting as much for the views as for the history — Fuerte de San Miguel has the best museum, San José el Alto has the best collections of shipwreck archaeology, and the Baluarte de San Carlos downtown has the dungeon tunnels.
Campeche is less visited than Mérida or the Caribbean coast — which is largely why it's worth going.