Syrtis Major is a "dark spot" (an albedo feature) located in the boundary between the northern lowlands and southern highlands of Mars. It is named after the classical Roman name for the Gulf of Sidra on the coast of Libya (classical Cyrenaica).

It was the first surface feature of another planet to be seen, by Christiaan Huygens in 1659. It is centered near 290° W and 10° N, extends some 1,500 km (930 miles) north from the planet's equator, and spans 1,000 km (620 miles) from west to east.

They are several theories about its formation. In the past, some guessed that it is liquid water, even though the temperatures and the air pressure seem to prevent this possibility. The research team that worked on the ALH84001 Martian meteorite from Antarctica have even suggested that they are bacterial growths, feeding off geothermal vents.

See also

• Exobiology