This unique nature reserve north of Františkovy Lázně features an extensive peat bog where pure carbon dioxide bubbles up from mofettes, and the landscape, with its bubbling mud, resembles the surface of the moon. Trail No. 23 leads directly to the main entrance area of Soos, but bicycles are strictly prohibited on the nature trail itself, which runs along boardwalks. At the entrance, next to the ticket office, museum, and restaurant, there is a large designated parking lot with sturdy bike racks where you can safely lock your bikes before entering the paid area.

Photo by Lubor Ferenc – Own work, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=146394847