Not sure if this is the right thread for this (could also fall under Media, though this is very spoiler-y).
Jon Montgomery was just on The Social and not only talked about the challenge we've seen in the previews (Rex's "mother of Cher!" Moment) but named it and showed a clip.
It's "The Monster" at Canada Olympic Park in Calgary, the fastest zipline in North America. The clip was Jon's challenge description where he says "When teams arrive, they must climb to the top of this hill and both take a ride on the fastest zipline in North America, called The Monster."