From 13th September until 10th October 2013 visitors can climb a temporary staircase to the sky, four and a half times the height of Big Ben. The Endless Stair outside Tate Modern, designed by architectural practice dRMM, is a landmark project of The London Design Festival 2013. The 436 metre interactive structure is made of a series of interlocking staircases, inspired by drawings of M.C. Escher. With 187 steps, the 7.7m tall Endless Stair is of the same height as a three-storey building, and will provide both Tate Modern and river Thames views. Open during daylight hours, the structure can accommodate a maximum of 93 people at a time.