The mountains  are giant and interesting places.   They are a  world  apart from very much of the rest of the world.  In addition they are an environment where  the wildlife thrives.  So you can,t say that they are not awesome.        At the beach you can  swim  wade or Sun tan yourself.  You can have a clam bake.  Play  Frisbee, volleyball and explore spots for   seashells  and  driftwood.  Everyone of these things boost  oxytocin ,  plus I guess endorphins and dopamine too.    This helps lift us up by the external stimulation into ourselves  then  it makes a internal process of chemistry.  So I will  have the beach be my choice!