An interesting piece of Quintana Roo island property has been put on the market for US$5,000,000. 

The island, called Cayo Culebra (Snake Key), appears to be privately owned by one Maria Vasquez Rubio, and consists of approximately 89 acres (36 hectares) of island land in the beautiful Mayan Riviera.  The catch is that the only human use of the property permitted is scientific ecological research; the construction of permanent structures is prohibited.

The listing agent is the LandRod Law Firm and Real Estate Office (in Mexico, a law firm is permitted to act as a real estate brokerage and a law firm notwithstanding the potential conflicts), which also has several other nice looking coastal properties listed for sale.