Although very small amounts of liquid water may occur transiently on the surface of Mars, limited to traces of dissolved moisture from the atmosphere and thin films, large quantities of ice are present on and under the surface. Small amounts of water vapor are present in the atmosphere, and liquid water may be present under the surface. In addition, a large quantity of liquid water was likely present on the surface in the distant past. Currently, ice is mostly present in polar permafrost. More than 5 million km3 of ice have been detected at or near the surface of Mars, enough to cover the planet to a depth of 35 meters (115 ft). Even more ice might be locked away in the deep subsurface. The chemical signature of water vapor on Mars was first unequivocally demonstrated in 1963 by spectroscopy using an Earth-based telescope. In 2008 and 2013, ice was detected in soil samples taken by the Phoenix lander and Curiosity rover. In 2018, radar findings suggested the presence of liquid water in subglacial lakes and in 2024, seismometer data suggested the presence of liquid water deep under the surface. Most of the ice on Mars is buried. However, ice is present at the surface at several locations. In the mid-latitudes, surface ice is present in impact craters, steep scarps and gullies. At latitudes near the poles, ice is present in glaciers. Ice is visible at the surface at the north polar ice cap, and abundant ice is present beneath the permanent carbon dioxide ice cap at the Martian south pole. We celebrate this event with an AI image of the moment NASA reveals water on Mars …