LEGO® Czech Hedgehogs | Tank Traps
 
In the 1930s an anti-tank trap was developed by the Czech military. It's purpose was to stop tanks in their tracks and reduce the speed at which the enemies travel across the battlefield. If the Czech Hedgehog was deployed with anti-tank mines. This design was basic but efficient, it was made up of interlocking metal beams which made the obstacle difficult to remove. It was often placed along coastlines or fields. At the coast it  could also defend against landing crafts like on D-Day.