Large Structures Melting Out of Antarctica

What appears to be some sort of structures have been observed in Antarctica. At first I didn't really quite see what they meant by structure, but after looking at some of the "enhanced" pictures, I can see what they mean. The first half of the video takes a look at one of the more recent discoveries. The second image is featured in an article from 2017 and showcases what appears to be some sort of dome structure.

Be sure to check out Behind The Scene's channel for the source material for this video:
https://www.youtube.com/watch?v=8chI-PPKutw

Track: VOYAGER 1, Odyssey by John Tasoulas
Creative Commons - Attribution 3.0 Unported
Video Link: youtu.be/jf2af9pa9UI