Massive Martian ice discovery opens a window into red planet's history

Newly discovered layers of ice buried a mile beneath Mars’ north pole are the remnants of ancient polar ice sheets and could be one of the largest water reservoirs on the planet, according to scientists at The University of Texas at Austin and the University of Arizona. The layers of ice are a record of past climate on Mars in much the same way tree rings are a record of climate on Earth.
Source: EurekaAlert, https://www.eurekalert.org