This is the edge of Antarctica, seen from sea level.
What looks like an enormous frozen wall is the exposed face of an Antarctic ice shelf, formed where glaciers and the Antarctic Ice Sheet flow off the continent and extend outward over the ocean.
These ice shelves can be hundreds of feet thick, but you're only seeing the portion rising above the water. Most of the floating ice remains below the surface.
And these aren't stationary walls. The ice is slowly flowing outward under its own weight. As it reaches the outer edge, enormous sections eventually fracture and break away into the ocean, a process known as calving. Some of those pieces become icebergs large enough to survive for years.
Antarctica contains roughly 90% of the world's ice and about 70% of its fresh water.
Seeing it on a map is one thing.
Seeing the sheer scale of its frozen edge from the water is something entirely different.