In the early 1900s, an extensive fortification system known as Stockholm’s permanent defense was built. It had two main stretches: the Northern and Southern fronts, designed to block and delay any ground invasions advancing toward the capital. The chain of bunkers and fortifications followed natural passes and key approach routes and became known as the “Sausage Line” for the cylindrical shape of its bunkers.
The project was initiated and financed by private citizen groups who raised money to purchase the land and construct the forts. The military engineering corps carried out the design and construction, but under civilian leadership. Concerned about their defense shortcomings, citizens wanted the forts as a precaution. With World War I just around the corner, the concern was not misplaced. Fortunately, the war never reached Stockholm. Once completed, the Sausage Line was handed over to the military and used until 1952.
A century later, many of the forts have disappeared, making way for new construction or simply succumbing to the forces of nature and time. A few sections remain, including Måndalsfortet (Moon Valley Fort), built in 1903. Located along Måndalsstigen (Måndal’s Path), it is one of the largest and best-preserved forts along the Southern Front and was intended to defend the Kumla Pass from land troops.
Today, the concrete bunkers remain in remarkably good shape despite decades of neglect. Still, neither the Swedish National Heritage Board nor the Stockholm County Administrative Board consider the Sausage Line to be of cultural or national interest, leaving it without formal protection.