This huge listed fortress occupies 58ha of land and has 640 rooms. It took 21 years to build from 1850 to 1871 and employed over 10,000 labourers. However from the outside, it appears almost covered in sand and seems almost invisible. A visit is the only way to appreciate the impressive dimensions of this stronghold. Rotating vaults, immense poles and the excellent craftsmanship of the bricklayers are just a few of its attractions. A tour will also reveal that during the Second World War, the fortress accommodated countless Jews awaiting deportation. The Soviet Army turned it into a munitions depot.