Tyrolean Traverse

Made famous in the movie Cliffhanger, for all the wrong reasons, a tyrolean traverse involves crossing a gap between two high points on a rope.  Despite the aforementioned movie, a correctly set up tyrolean traverse is a safe but often daunting method of crossing a gap or stretch of water (especially when climbing sea stacks). 

Obviously, it goes without saying that these should be set up by an experienced climber as the consequences of an incorrect setup can be fatal.