You may think that images of mountains as design elements are only relevant for travel and tourism sites, and at one time that was probably the case. However, these days, as designers turn more and more to emotion in website design, mountains can be used to convey calm, freedom, activity/sport, strength, and many more emotions, so we can see mountain images used in a variety of websites now.
Of course, they are still often used in travel sites. This round-up features website designs featuring mountains, hills, glaciers, icebergs, cliffs, rocks, etc. They may be the main focus of the design, the background, or just a small element within the design.