a dangerous place from which to view the world

a gloomy place, with wide wastes of hot sand where nothing grows save a few utterly uninviting cactus plants

a place of dryness and heat

a place that has few, or sometimes even no, life forms

a place where lack of water is severely limiting to living things most of the time

a place where there is hardly any water and it has vast expanses of sand

a place without expectation

Mainly a state of mind. Very important for several reasons: 1. easy place to dispose of 'accidents' 2. where The Snake resides 3. where Las Vegas is located. And Old Mexico.