I'm a sucker for odd and overly-specific attractions, so the Sanya Orchid Park is a must-visit place for me.
It has over 2 million orchids! More than 3,000 species, including all the really rare ones. Actually, I don't know anything about orchids, but this place is still very fun. It's obvious that someone put a lot of thought and money behind this attraction, and it's a very pleasant diversion.
Cost: 125 RMB
Hours: 07:30-18: 00
Transport: ride the #16 bus or the tourist special line 2, and get off at the tropical rainforest station