STUTTGART, GERMANY - AUGUST 30: General view of a tunnel entrance at the construction site of the Stuttgart 21 railway station construction site on August 30, 2016 in Stuttgart, Germany. The Stuttgart 21 project, also called S21, encompasses not only a new main railway station for the city but also an urban development program and 50 kilometers of rail tunnels. The project has provoked large-scale protests by people angry over the planned uprooting of trees in an adjacent park as well as those critical of the enormous financial cost. A ground-stone laying ceremony for the new railway station is scheduled to take place in September. (Photo by Thomas Niedermueller/Getty Images,)