A sunken city, columns, arches, bronze lions and gates spread over 600,000 sq ft of seabed, encrusted with coral. It is also a…A sunken city, columns, arches, bronze lions and gates spread over 600,000 sq ft of seabed, encrusted with coral. It is also a genuine cemetery, cremated remains are mixed into the structures. Enormous, silent, and unlike anything else on the map. Opened 2007 as 'the Atlantis Memorial Reef', conceived as a green-burial alternative that doubles as an artificial reef. Fish biomass on the site now exceeds nearby natural hardbottom, the strangest conservation success in Florida. Anchorage: Site moorings; day trip from Miami/Key Biscayne. Hazards: No site-specific hazards noted, brief normally. Plus