Yes, Human Body. 人体。And up to 3 entries are allow.
I've see different interpretation of human body.
It's quite interesting. You shoud have a look:
https://steemit.com/trending/steemitphotochallenge
If you are interested for theme announcement, you should follow @jamtaylor.
Here's the latest announcement:
https://steemit.com/steemitphotochallenge/@jamtaylor/steemit-photo-challenge-spc-18-winners-and-new-theme-announcement