Beginning in the autumn of 1940, German Luftwaffe pilots bombed London for 57 consecutive nights. It began on Sept. 7, when 348 German bombers and 617 Messerschmitt fighters appeared in the clear skies above the British capital and began to pound the area with explosives. In the months that followed, great numbers of aghast Londoners fled to the countryside. But many more stayed put, through air raids that flattened great swaths of the city and killed 20,000 residents. When the bomb shelters filled up, tens of thousands of Londoners filed into Underground stations, where they slept, packed like sardines, on the concrete platforms.

This September marks the 75th anniversary of the Blitz (short for the German Blitzkrieg, for “lightning war”), Nazi Germany’s eight-month wartime bombing campaign against Britain. This fall, London’s robust tourism industry will commemorate the capital’s time under siege.

Already, assorted Blitz-themed walking tours abound. On a recent Sunday, several dozen tourists met near the Thames River for a “Westminster at War” tour (London Walks, £10, about $15; walks.com), led by a bespectacled gentleman tour guide who sternly warned the attendees that they “mustn’t shilly-shally,” for there was much to see.