From the 1950s through 1970s, various research expeditions performed surveys of the Mediterranean seabed which revealed a layer of salt buried below the surface, called the M Reflector. The presence of this deposit indicates that the Mediterranean sea had once dried up before subsequently filling with water again, an event known as the Messinian Salinity Crisis. Based on a survey of the M Reflector taken the coast of Spain, Litwittz’s drawing shows the two strata of the earth beneath the sea, revealing at once the Mediterranean’s past and present.