Several fortifications were constructed at the end of the 19th century in the territory where Karosta now lies, in the centre of Liepāja and near the southern border of the city in order to protect the navy base from potential enemy attack. In November of 1908, the Liepāja Fort was demolished because it was admitted as being a strategic error. The fortifications were blown up twice in order to demolish them. Only partially blown up parts of the artillery batteries, underground structures, and powder warehouses are still standing today.Just like Karosta, the Northern Fort was a closed military territory during the years of Soviet occupation. Today these partially exploded labyrinths of history are free to be explored.