Bratislava has always been the city on the border. The city itself and its surroundings were fortified since the medieval ages to the present times. The latest fortress system was built just before the WW2 by democratic Czechoslovakia to repel Hitler's invasion. Due to the political decisions from september 1938, this well prepared defense system could not have been used and Hitler invaded our land without a fight. Once, the war had come to an end, the communist regime raised up the Iron curtain that divided Europe. Bratislava, as part of the eastern block has received than another "defense system". This one has prevented citizens to freely travel to the western countries. The edge of the city, with massive bunkers, became a part of strictly patrolled "no-trespass area". Due to the fact that for more than forty years, no one can approach close to the border, our technical heritage - the czechoslovak fortress system, fell into forgotten.