Yucatán was a Mexican state. Its capital city was Mérida. According to the Second Doctor, Quintana Roo was another of its cities. (TV: The Enemy of the World [+]David Whitaker, Doctor Who season 5 (BBC1, 1967-1968).)
In 2012, Jo Jones planned to visit Yucatán as part of a conservation tour of the country. (AUDIO: The Infinite Today [+]Error: Code 2 - no data stored in variables, cache or SMW.)