Very few people back in the mid-19th century could probably have imagined that the massive fortifications designed to defend the Swedish capital against any invader would never be finished. Even fewer would have predicted that they would end up in an office building lobby and occasionally be used as a yoga studio.

When construction on the Johanneshov fort started in 1859, this area was an uninhabited and undeveloped piece of land. Though rather nondescript, the location was ideal for a sconce (small fortress) in a strategically important area.

The late 1850s were a turbulent time in the region. Sweden had 50 years earlier lost Finland to Russia, Europe was still recovering after the Napoleonic Wars, and the Crimean War had raged just a few years earlier. Although Sweden was not directly involved in the war, it still reached all the way to the Nordics and the Baltic sea, something that led Swedish authorities to plan for a new defense line in Stockholm.

There was just one problem: Technological advances and changes in military tactics had made the fortification obsolete before it was even designed. In 1860, the year after construction started, the Swedish parliament decided to abandon the project. The half-built sconce was left standing in an incomplete state.

It would take another 50 years until a sports facility was built in the area. Now, one of the sconce’s walls—a massive 230-foot-long (79-meter-long) stretch of stone complete with embrasures—has been seamlessly integrated into a modern office building environment.