Bedrock Admin Base
From Simply Vanilla
Not much is known about this base, but it consists of 2 bedrock medium boxes.
One is located at -100030/90/-100020 and the other is at -100000/32/-100000
ShaneTheCreep has done a video tour when he visited it. https://www.youtube.com/watch?v=BvORmyybb9Y
14:50 - 18:30 Upper bedrock box
20:00 - 22:55 Underground bedrock box