Semmering Pass, mountain pass, alt. 984 m, at the border between Lower Austria and Styria, between Central Alps and Limestone Alps, crossed by the Semmering Railway and Semmering road. Located between the limestone massifs of the Rax and Schneeberg mountains in the north and the gneiss and mica schist ridges of Stuhleck Mountain and Wechsel Region in the south, the Semmering Pass is characterised by steep limestone rock faces, craggy rocks, broad mountain ridges and wide valleys. There are magnesite, iron ore and gypsum deposits in the soft schist zone (near Schottwien). Linking the Muerztal Valley with the Vienna Basin, the Semmering Pass has formed the border between Lower Austria and Styria since 1254; watershed between Wiener Neustadt Basin in the east and Muerztal Valley and Froeschnitztal Valley in the west. The Semmering road, which links Gloggnitz (Lower Austria) and
Muerzzuschlag (Styria, a simple mountain path existed as early as the 12th century), was constructed under Emperor Karl VI (monument on the summit of the pass) in 1728; extensive serpentines built to facilitate access under Emperor Ferdinand I in 1841; replaced by a new route between 1956 and 1958, further extensions later. Due to its beautiful landscape and large coniferous forests the Semmering Pass is an ideal high-altitude health resort and winter sports area. Tourism reached its peak around the turn of the 20th century, but the Semmering Pass continued to enjoy great popularity until the Second World War. The fall of the Iron Curtain led to an upswing in tourism in the 1970s.