Wide angle lenses have a short focal length and an increased depth of field. They are called wide angle as they cover a large area in their snapshots. Hence they are used to shoot landscapes. Here is the wide angle lens I use :
Here is a wide angle photo of fishermen packing their nets after a fishing trip :
Notice the vista of the beach in the background. With a wide angle lens objects in the foreground appear huge :
The greater depth of field seen with a wide angle lens can be further accentuated by using a small aperture at a large F number. The small aperture may require you to use a tripod in low light conditions as a slow shutter speed will result.
A wide angle lens enables you to capture a whole building :
or bring out the beauty of large skies and cloud formations :