A large, roughly circular depression on Mars over 1500 km wide, perhaps an ancient impact basin, centred at +27° lat., 40° W long. Its floor is over 2.5 km below the so-called Martian datum height (the zero elevation contour, at which the average Martian atmospheric pressure is 6.1 mb). Many ancient channels that are thought to have once contained water run into Chryse. Radar sounding of Chryse Planitia shows signs of water ice 1 km below the surface, hence it is a promising place to look for signs of Martian life. Chryse Planitia was the landing site for Viking 1 in 1976 and for Mars Pathfinder in 1997.