The Fortress of Terezín was founded in 1780 by Emperor Joseph II in order to defend the Czech borders against attacks from the north. It represents the pinnacle of bastion fortification architecture in Europe. An intricate triple ring of massive ramparts allowed the defenders to cover the entire foreground with crossfire, attackers had nowhere to hide. The still functioning water defense system not only allowed to flood the extensive basins surrounding the fortress, but also to create an artificial flood wave, destroying every enemy in its path. In addition, several dozen kilometers of underground mine tunnels zigzag beneath the fortifications of Terezín. These enabled blowing up the advancing attacker with underground explosions. All this can still be found in the fortress today. Its level of preservation makes it a unique cultural heritage site on the UNESCO Tentative Lists.