Off Indonesia's coast, a hidden city under the ocean has emerged. Discoveries in the Madura Strait unearthed 140,000-year-old skull fragments belonging to Homo erectus alongside 6,000 animal fossils, including Komodo dragons and elephants. This site might be the first physical evidence of Sundaland, a prehistoric landmass connecting Southeast Asia. Fossils show cut marks, hinting at early human hunting techniques. Recent findings propose a broader Homo erectus range within the drowned Sundaland, offering clues on human history.