While in Essen, we were able to visit one of the sites that the public water board Emschergenossenshaft was working on. When we first arrived we were greeted by a man who worked with the company. He gave us a presentation of the work they were doing such as remediating the Emscher River (former above-ground sewage) and other projects they have done in the past. At the current site we were at we were able to put on hard hats and construction vests to enter the site. We walked deep underground into a large tunnel system that they created. We walked deep into the earth about 10 flights? of stairs and it instantly got colder. It was really hot this day so it felt great!