Akiyoshidai Quasi-National Park
Akiyoshidai (秋吉台), meaning Akiyoshi Plateau, in Yamaguchi Prefecture is a Quasi-National Park of Japan. It is a part of the largest karst topography in Japan.
Akiyoshi is made of limestone, which is believed to have developed from coral reefs back in the Paleozoic era. Trees said to have appeared in the area for the first time 500,000 years ago. Many fossils from ancient Japanese rhinoceroses, tigers, and elephants have been escavated from the plateau, giving scientists some idea of what sorts of creatures first inhabited the region.
Because the area is made of limestone, Akiyoshi Cave, the largest cave in Japan, formed over a span of 300,000 years. Today the cave is estimated to be 420,000 cubic meters.
Akiyoshidai is largely covered with grass. Its grassland is the second largest in Japan and is kept by burning off dead grass in February. You can see thousands of limestones all around Akiyoshidai, as is characteristic of karst.
Flora and fauna
Akiyoshi Cave and the main observatory can be reached on foot, but cars or "karst taxis" are necessary to reach other caves. A one-day taxi pass costs ¥800.