Anyone who has read Slaughterhouse Five learned about the Allied destruction of Dresden during World War Two. Most accounts of the attack recall it with regret at the massive destruction of innocent life and property in one of Europe’s most picturesque cities.

Looking back on decisions made during warfare, it’s always easier to claim that one attack was more heinous than another. In the heat of battle, when the very notion of freedom and justice is under threat in the face of a ruthless fascist regime, all bets seem to be off the table.

And yet, there were some moments in World War 2 that seemed to cross a line. The idea that there were “civilized” rules of war that somehow implied that attacking ordinary citizens was wrong, now seems quaint in the present era when dictators will go so far as to gas their own citizens.

The Palm Sunday 1942 bombing of the German port city of Lübeck was one of the moments of war that seemed to indicate a new threshold had been crossed.

Lübeck was considered to be an architectural treasure and was largely bereft of military targets. The Royal Air Force decided that they needed to begin a program of bombing civilian areas in an effort to diminish German morale. They had also recently developed incendiary bombs and wanted to deploy them in an older city that was sure to burn rapidly.

The bombing caused major destruction and civilian deaths, but did little to diminish German morale. As a retaliation, the Luftwaffe initiated a series of bombings against English cities known for their picturesque charm rather than for military importance. Bath, Exeter, Canterbury and York were bombed by the Nazi’s, but with limited success.

These raids were known as the Baedecker Blitz because the targets were selected from a 1937 Baedeker travel guide of Britain.