I think finding beauty in nature and having a sense of humour are both linked to our natural drive to learn which in itself has given us an evolutionary advantage

laughing is a reaction to discovery (what comedians call "pull back and reveal") as for beauty in mountains I suspect that has more to do with a larger love of big views.

in The Humans That Went Extinct by Clive Finlayson, the author talks about the changes in environments that led to the swift divergence of homo sub-species. most notibly the early change in our development as woodlands gave way to grasslands leading to our ancestors walking upright. He mentions an experiment involving children from a young age but varying ethnic backgrounds being shown pictures of different landscapes and something that humans almost all agree on is a love of wide open land.

mountains help give a sense of perspective and when viewed from a distance act as a fixed point of reference (like the stars) so another evolutionary advantage I can see from being drawn to views of mountains is that it might help you find your way home.

Humour is a funny thing...

I notice that I can watch a comedian on my own and think they're hilarious while not actually laughing but if i see them with friends at a club I'm unable to stop myself so that suggests something social is going on, shared laughter is a sign of cohesion. If you haven't read Daniel Dennett's "Consciousness Explained" type this into google:

"Daniel Dennett: There is a species of primate in south america" (took me to the google book)

that said, my cat Sagan has a sense of humour so I don't think it's purely human (unless it's purely human to think cats have asense of humour of course)