Sticking out above Rottweil like a sore thumb, the futuristic, environmentally progressive Testturm is the brainchild of steel-engineering giant Thyssenkrupp, who aims to speed up skyscraper construction. At a whopping 246m high, it's the tallest elevator test tower in the world. At the time of research, it was open to the public, with Germany's highest visitor platform (232m) commanding staggering 360° views of the Black Forest, Swabian Alps and – on clear days – the Swiss Alps .