Betcha didn't know China could look like this. Curious wanderlusters should head to the island of Hainan, in the South China Sea, before it gets any more popular. The tropical isle -- with sprawling rainforest and pristine volcanic hot springs -- is a totally unexpected retreat from mainland Asia. On Hainan, you can swim, surf, golf, soak in hot springs, camp in the rainforest or zip line through tropical trees.