The peak Ma'anling (Saddle Mountain), located in the Shishan Geopark in Haikou of South China's Hainan Province, wins its name thanks to its twin volcanoes. The Ma'anling volcanoes are the biggest among all volcano clusters that were active between 27,000 to 1 million years ago. The altitudes of its north peak and south peak are 222.2 metres and 186.75 metres respectively, both of which are surrounded by more than 30 smaller sized hills.