The Hour Glass Sea on Mars

Galileo was the first person to look at mars through a telescope, but he didn't make significant discoveries about it. The first person to observe and draw a feature on the surface of mars was the dutch scientist christian hoygens in 16 59. We now know this dark patch as curtus major, a volcanic plan covered with darker basaltic rock from extinct volcanoes. This was the first documented surface feature seen on another planet other than our sister planet, the moon.