Edzná Ruins are about 61 km (39 mi.) s.e. of Campeche off Mex. 188; take Av. Central out of the city, following signs for the airport and then Edzná. This Mayan city was first inhabited about 400 B.C. and abandoned by the mid-15th century; as is true of other archeological sites in Mexico, the reasons for its decline remain a mystery.
The closest major ruins to Campeche may not be worth the trip if you've seen Chichén Itzá or Uxmal, but there is one standout building: the 98-foot-tall Temple of Five Stories (Templo de Cinco Cuerpos), a five-level structure with a central staircase and an impressive roof comb at the top. South of this temple is the Temple of Masks, with carvings of heads that have jaguar-like faces.