Everyone associates Las Vegas with casinos, however just outside the city is the magnificent Spring Mountains range. Rising to 11916ft at Mount Charleston, this is a great place for hiking.
Mary Jane Falls at 9200ft is a seasonal waterfall - you will only see water here in the spring from snowmelt. It was a trickle when I was there in late March. Whilst hardly Aber Falls or Corrieshalloch, it is still a contrast to the dry desert floor.