The Xmuch'haltún Botanical Garden sits inside the Baluarte de Santiago, one of the original colonial bastions of the city wall. The contrast between the thick military stonework of the fort and the tropical garden it now contains is quietly surreal — palms, ferns, bromeliads, and flowering trees growing where soldiers once watched for approaching pirate ships.
The garden is small — you can walk through it in 20 minutes — but it's a pleasant shaded refuge from the midday heat, and the setting within the ancient walls gives it character that a more conventional botanical garden would lack. The collection focuses on species native to Campeche state and the Yucatán Peninsula, with labels (in Spanish) identifying the plants and their traditional uses. Free entry.