Festung Crestawald, Military fortress museum in Sufers, Switzerland

Festung Crestawald is an artillery fortress in the mountains with underground tunnels, weapon emplacements, and exhibition spaces displaying 20th century military equipment. The site preserves original buildings and infrastructure that give visitors insight into the defensive military structure of this mountain region.

Construction of the fortress began in September 1939, shortly after the start of the war, and was completed in June 1941. Its two 10.5 cm Kanone 35 L42 guns, named Silvia and Lukrezia, were Swiss-built versions of a Swedish ship-gun design with a range of 17 km, or 23 km with reduced accuracy. They could shell the Splügen and San Bernardino pass heights while remaining out of reach of enemy artillery. The site stayed secret through the Cold War and opened to the public in 2000.

Special exhibitions have been held here, including "Wolves in Sheep's Clothing" in 2005 and "US Bombers over Graubünden — Flying Fortresses at the Crestawald Fortress Museum" in 2010/2011. The site is run by an association founded after the fort was abandoned in the mid-1990s, which turned the bunkers into a museum.

Access involves mountain paths leading to different parts of the fortress, so sturdy shoes and some physical fitness are needed. Guided tours or audio guides are helpful for understanding the site fully, as they explain the underground spaces and their original functions.

The two main guns were named Silvia and Lukrezia; they were Swiss-built versions of a Swedish naval gun design and could fire up to 23 km, far enough to hit the passes without being exposed to enemy counter-battery fire. Around 95 soldiers were stationed here at a time, and 10,000 shells were stored for the pair.