Antarctica is where Second Impact occurred on September 13, 2000. An in-universe cover-up describes the event as a meteorite colliding into Earth at Mt. Markham on Antarctica's Pacific coast, somewhat east of New Zealand. In reality, the disaster was caused by the explosion of the First Angel, Adam.
All Lilith-based life, even down to microbial life, in the surrounding area were destroyed as a result of Second Impact. This is due to the Anti A.T. Field Adam briefly spread between awakening and exploding soon after. The ruins of Antarctica are now the true "Dead Sea". In addition, the continent's ice shelf melted, raising the global sea level, and the rest of the landmass was submerged by the sea. All that is left of Antarctica now is a hostile landscape devoid of life, with the occasional pillars of salt protruding through the surface of the red ocean.
Before the Second Impact, the White Moon along with Adam was discovered in Antarctica. This prompted the Katsuragi Expedition which was sent there to investigate, and for Dr. Katsuragi's research into the limitless power of the S² Engine. An experiment conducted by this research team caused Adam to awaken, leading to Second Impact.
Real Dead Sea
The Dead Sea is a lake on the border of Israel and Jordan. It is considered to be the lowest exposed point on the Earth's surface, with it's deepest point at approximately 400m. It is called the Dead Sea due to its high salt concentration, approximately 35%, which prevents fish or other macroscopic aquatic organisms from surviving, although trace amounts of bacteria and microbial fungi are still present.