In defence of the Realm

At the outbreak of World War II with an invasion of "This scepter’d isle" a real possibility a 12 mile long line of concrete blocks was built along the beach from Aberdeen  to Newburgh. The rocks set into the concrete were intended to tear off the tracks of any German tank attempting to climb over the traps. Thankfully they were never put to the test.
80 years later we seem to have learned few, if any,  lessons about the utter madness of war.