During World War II, Switzerland was in a uniquely tough spot amidst the seats of fascist power such as Germany and Italy. Shoring themselves up against possible invasion, the country created the Promenthouse Line, which still exists today under a much sweeter name - the Toblerone Line.
The Promenthouse Line is a long trail of anti-tank defenses that consisted of 12 fortresses linked by miles of cement wedges known as “dragon’s teeth.” Running from the Jura mountains to Lake Geneva, the line was more of an inconvenience than a wall. The 16-ton hunks of concrete presented an impassable obstacle for tanks but could easily be destroyed by explosive ordnance. Luckily the defenses never needed to be tested, and the trail of stone teeth remains to this day.
While there have been motions to dismantle the defensive line, it still survives to this day, albeit by a different name. Thanks to the defense’s resemblance to the distinctive Swiss chocolate bar, Toblerone, the increasingly moss-covered dragon’s teeth have taken the company’s name for their own.
A Toblerone trail has even been built up along some portions of the line, with paths and stairs for hikers and bikers. Visitors can also visit some of the fortresses along the way.
Know Before You Go
The easiest part of the toblorone line to visit is across the street from the villa rose (link). To get there keep walking south past the villa until you reach a bridge with a staircase that goes down. This allows you to go under the highway in a safe way. After that walk back along the road until you reach the woods, then follow the path and you'll see the toblorones about 20m further. You can keep walking along the path to the station or where you parked tour car.