Often said to be one of the first mountain railways in the world, this awe-inspiring line also boasts the heady title of being one of the few railways to hold a UNESCO World Heritage listing. This title is for good reason, because the line, which has been running since 1854, passes over and through some of the most incredible scenery on the planet. Running over 41 kilometers from Gloggnitz to Mürzzuschlag, the line winds through the verdant beauty of the Semmering Pass, and passs over 16 viaducts, 110 bridges, and through 14 tunnels. Rather than disrupt the natural beauty of the valley, the line was designed to work in harmony with its surroundings, and therefore the views from the trains that run along it are second to none. In 2012, a base tunnel through the valley began construction, and it is expected to open in 2026, over 170 years after the line first opened.