Untersberg is the mountain Salzburg keeps on the horizon: close enough for a half-day trip, high enough to feel properly Alpine. The cable car from Grödig climbs fast to a ridge where the city, the Salzach valley, and the limestone peaks beyond line up in one broad panorama.
This is one of the easiest ways to add mountain air to a Salzburg stay without committing to a full hiking day. Weather matters, so check visibility before going; in cloud, the ride is expensive for very little reward, while on a clear day it is one of the best views in the region.