Underground River. Where is the longest one?

I read somewhere that the longest one is under the desert in China.. However, maybe its dried up since then and one in Aftica is longer. Does anybody really know for sure?

Is it the Sac Actun system, discovered by divers Robbie Schmittner and Steve Boagarts in January 2007, the full length of which is 153.6 kilometers and depth 72 meters at the most, underneath the Yucatán Peninsula in mexico and Balize?

Rivers and waterways are like veins and arteries. They are of huge importance in the health of our planet and home...yet we treat them as garbage disposal units and abuse the creatures that live therein. Perhaps the underground rivers have escaped the worst of man's interference.

I'm learning too. I didn' even know that there were "underground" rivers?

Our Floridian Aquifer that runs the length of the central part of the state of Fl. is called an underground river because it flows between layers of limestone does that count? It pops up here and there as sulpher springs too. It flows all th way into Miss., Georgia, Alabama, and S.Carolina. When it pops up as Springs these springs become above ground rivers such as the Blus Spring Run and Silver Springs River etc. If it counts, then it is about 400 + miles long. Not counting the little rivers that it feeds above ground. Shalom~Adoniah