Herne was targeted by the RAF on 4 June 1940, early in World War II, and air-raids became daily and nightly occurrences. On one occasion, three high-explosive torpedo-bombs were dropped, severely damaging a number of houses in the Vincke-Strasse (only some of the outer shell had remained) and resulting in the deaths of all the inhabitants. Phosphorus bombs were dropped in several locations and caused fires that lasted for days. Because Herne had a lot of undeveloped land, however, damage during the following years of often multiple daily and nightly air-raids with many "blind hits" was not very extensive, in contrast to more densely populated and developed areas like Essen Werke and Wuppertal, which were almost totally erased. Herne was probably targeted because of the many coal mines as well as the Rhein-Herne Kanal with two double chambered locks (a total of four chambers) at that time, within the city-confines of Herne and at the northern edge. The canal was the major mode of transportation for coal and coke from the many coal mines in the area to the factories for iron ore to be processed into steel (Blau-Stahl) and coal being transported along the inter-connecting waterways in all other directions, to be used for industrial as well as domestic use. In particular, the Bridge across the Rhine-Herne Canal closest to the easternmost double-chambered lock and the wharf (for repair of damaged Canal-going vessels) on the North shore, was hit and taken out, so that there was no connection across the Canal at that location (at the time, the Street there was known as Ludwig-Strasse but has been renamed since to Pöppinghauser Strasse). The locks have been renovated, each of those two double-chambered locks having been combined into just one single-chambered lock each, albeit considerably larger chambered, to accommodate much larger vessels.