“Mare, plural maria, any flat, dark plain of lower elevation on the Moon. The term, which in Latin means “sea,” was erroneously applied to such features by telescopic observers of the 17th century. In actuality, maria are huge basins containing lava flows marked by craters, ridges, faults, and straight and meandering valleys called rilles and are devoid of water.” - Encyclopaedia Britannica
Yes, a mare in the moon!