Stairs

This image was taken at the Zeche Zollverein in Essen when we were invited by some very good friends for a weekend. It is an amazing place and more than worthwhile to visit. The look down into the staircase is a little bit like an Escher drawing, especially due to the curved stairs which have attached for the visiting tour. Other than that it is very hard to find any round shapes on the entire architecture.
Today the entire Coal Mine Industrial Complex Zeche Zollverein is UNESCO World Heritage Site, open for visitors.