Mars was discovered by visual observation without instruments. The first mention of observations of Mars occurred in ancient Egyptian records dating back thousands of years. In 1610, Galileo Galilei was the first person to observe Mars through a telescope.
Since Mars is visible with the naked eye, it is impossible to tell who first discovered the planet, though Egyptian astronomers provided the first known written observations. Mars was depicted in the tomb of pharaoh Seti I, who died around 1279 B.C. It also appeared on a star map in the tomb of an ancient Egyptian architect named Senenmut. By 1045 B.C., Chinese astronomers had also recorded observations on the movement of Mars. Babylonian astronomers kept detailed records of Mars observations during the Neo-Babylonian Empire beginning around 625 B.C. Plato listed Mars in his order of the planets in "The Republic," published around 380 B.C.
Although Galileo used a telescope to study Mars, he was unable to discern surface detail. In 1659, Dutch astronomer Christiaan Huygens first illustrated the topographical features of Mars. Since that time, many astronomers have noted additional details on the surface of the planet. In 1965, the NASA spacecraft Mariner 4 flew close to Mars and took detailed photographs. In 1976, NASA spacecrafts Viking 1 and Viking 2 landed on Mars and sent back photos from the planet's surface. Three spacecraft orbit Mars, and two robots travel the surface gathering photographs and information, as of 2014.