The sport of cliff diving has evolved out of high diving as an adventure sport. The sport combines aerobics with height and daredevil athleticism. The courageous athletes of the Red Bull Cliff Diving World Series return to Possum Kingdom Lake on Friday and Saturday. Cliff diving started as an adventure sport performed by thrill seekers. Today the sport has evolved into a sophisticated athletic competition. Red Bull sponsors the Cliff Diving World Series with nine tour stops from June to October. Possum Kingdom Lake near Graham kicks off the series, and provides the only U.S. tour stop this year.  The competition starts ...