File:Antarctica Topography.jpg

Summary
A 3-D reconstruction of Antarctica's topography beneath its 2-mile ice layer created using radar survey data. The continent was relatively flat with a 'lazy river' running through what researchers describe as a 'spectacular valley' drained by other slow-moving rivers.

Photo credit: Stuart N. Thomson/UA department of geosciences.

Source: https://www.livescience.com/27715-antarctica-before-ice.html