MEGA is a group of submarine megalithic structures located NW of Cape San Antonio, at a depth between 600 and 750 meters on a marine depression with a maximum slope of 6 degrees. Lying on this depression are rocky features protruding from the sandy seafloor. These are cubic, pyramidal, parallelepiped and crest-like blocks with smooth and flat surfaces. Below is a 3D digital map of the seafloor; water is not shown.

On the map (above) the Shoal of San Antonio stands out (in blue) as the highest underwater peak with MEGA lying at the foot of it (between 21.85 and 21.9) within a somewhat uneven valley. The deep trench (top-right) follow the trend of a very important deep seated fault.

The exact location of the megalithic structures is shown here. The area is situated on a valley-shaped submarine depression at the northeastern edge of the Strait of Yucatan, between the Cape of San Antonio and the Shoal of San Antonio. A strong marine current from the Caribbean Sea flows in over this area, carrying large amounts of plankton, feeding the Gulf Stream. Due to this current there is a thick deposit of organic sands and strong erosion acting on the exposed submarine rocks.