>>15792490it's a pristine (no human involvement + Frozen) area from before the current Human civilization.
From there its literally anyone's guess
Biological entities (including bacteria and viruses) which the current humans have no resistance too
Ancient technology from before Atlantis and Mu
Because of Global warming they can no longer keep it contained and underwraps (for good or bad)
There is a very interesting story about an artifact that was unearthed in Iran then traveled to Antarctica for safe keeping. Via the Russian Orthodox Church leader