Early in World War II, Germany relied heavily on the great striking power of its fast-moving tank formations. To defend against the threat, the Czechs lined their borders with large iron obstacles shaped like toy jacks. Though not immovable, they cause tanks to get stuck after driving over them. While the Nazis went on to annex Czech territory in the Sudetenland, these obstacles, known as “Czech hedgehogs,” caught on with other combatants and were later employed in what famous battle? Discuss