While no specific date can be identified for the discovery of Mars, knowledge of the planet dates back to ancient civilizations. Ancient Romans, Egyptians and Chinese astronomers independently discovered and named the planet.
Since the 16th century, astronomers have made a series of additional discoveries about Mars. In 1576 Tycho Brahe calculated the planet's position, while Dutch astronomer Christian Huygens discovered Mars' first geographic features in 1659. Additional discoveries were made when Mariner 4 flew past the planet in 1965. In the 21st century, scientists made additional discoveries about the red planet's history and habitability with orbiting satellites and rovers Spirit, Opportunity and Curiosity.