Before the WW2, countries were preparing for the war, creating defense lines. France made the Maginot line, Germany the Siegfried line, while Romania made a line, later called by the people, Carol defense line. This defense line was supposed to protect Romania from Hungary and was 300 km length, from Maramures to Arad County.The construction begun in 1938 and was finished in 1940, containing 320 bunkers positioned to form 2, 3 or 4 lines of defense, in depth.