This awesome rollercoasteroid staircase is underway in Germany:
The walkable, large outdoor sculpture Tiger & Turtle – Magic Mountain is currently in construction on the Heinrich Hildebrand Höhe in Duisburg Wanheim (D). It overtops the plateau with the artificially heaped-up mountain by 21m | 23yd so the visitor can rise by more than 45m | 49yd above the level of the landscape and enjoy an impressive view over the Rhine.
Tiger & Turtle – Magic Mountain / Heike Mutter + Ulrich Genth
(via Crib Candy)