Sangumburi is a crater with a perimeter greater than 2km. It's considered a Natural Monument, and is located on the southeast side of Jeju-si city. It is a flat crater about 650m wide, 100m deep and 2070m in circumference. It's one of three Volcanic craters on the island, the other two being Sunrise park and the lake atop the central Mount. It is located in the center of the island and it's funny because they say that inside the crater, there are plants and animals that don't live in other areas of the island. Today biologists and other scientists are studying this area. Timetable: November 1 - February 28: 8:30am-5pm.