The document summarizes ancient cave dwellings and megalithic structures found across Taiwan. Over 100 artificial caves have been discovered, dug out by ancient Taiwanese people for shelter during an ice age over 10,000 years ago. These caves show sophisticated design features for ventilation, drainage, and defense. Taiwan also has numerous megalithic structures, including stone towers, piles, pillars, and walls, demonstrating an early civilization. The caves and megaliths provide evidence that Taiwan was a center of ancient culture in East Asia.
The document discusses evidence that mega-tsunamis from volcanic eruptions and flank collapses destroyed ancient civilizations over 50,000 years ago. Specifically, it notes that as the last glacial period ended around 12,000 years ago, stress imbalances triggered eruptions of stratovolcanoes located on shelves surrounding Asia. Landslides of these volcanoes would have generated mega-tsunamis over 100 meters high, capable of wiping out coastal settlements and islands across the northern hemisphere. The waters northeast of Taiwan in particular contain evidence of undersea volcanoes and faults that could have historically generated tsunamis impacting ancient civilizations.