Don Juan Boulder in Wonderland of Rocks in Joshua Tree Nationalpark. This route is called “the Duke” and is given an A0/5.9 rating. A0 is the lowest rating on the aid climbing scale. Aid climbing means ascending a rock with the help of gear. In this case it is a fixed rope that needs to be lassoed over a horn at the lip of the boulder! YES… Get your cowboy on and lasso the horn – ascend the rope – then enjoy beautiful and classic 5.9 Joshua Tree slab climbing. With this climb being the easiest way to get up “Don Juan”, not many people can claim to have been up there (it may take forever to actually sling the horn on its sweet spot). Who’s up for a try? Gotta love these shenanigans!