Dia for Mac?

I was wondering if there was something like Dia for Mac. I remembered I used that for documenting and create the basic source classes for my final university project, and I was wondering if it would be possible to have it running on mac. First searches are very negative, and I couldn't figure out how the Class Diagrams of XCode (the development environment for mac) worked (maybe I was way too sleepy...)

Anybody, any suggestion? :-)