Classified historical monument, the Great Cannon of Zillisheim is a vestige of the 1st World War. The site was built in great secrecy at the end of 1915 by German troops. The cannon was then moved to other strategic points. The site was cleaned in 2017 and today retains the underground galleries but especially the large concrete tank. 22m wide and 4.60m deep, it housed the canon, with its central pivot and turntable.