«Some of the observed features included ancient river beds, craters, massive extinct volcanoes, canyons, layered polar deposits, evidence of wind - driven deposition and erosion of sediments, weather fronts, ice clouds, localized dust storms, morning fogs and more,» NASA wrote in a summary of the mission. (space.com)
We will swim up through the cavern to the upper most lip and then circumnavigate the entire blue hole, seeing ancient river beds and waterfalls that were created during a previous ice age. (smallhope.com)
Using open data from NASA, OS plotted contour lines for the area in 250 meter intervals, giving a clear look at the many ancient river beds and crater marks that cover the planet's surface. (visualnews.com)