STUTTGART, GERMANY - AUGUST 30: Workers are seen in a tunnal 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,)