Fall of Eben Emael

In early May 1940, the fortress of Eben Emael was a potent sentinel over the Belgian–Dutch borderlands. The fortress covered 75 hectares on the surface, had 5km of tunnels underground and was studded with bunkers, gun turrets and casemates. Add a garrison of 1,200 men and the natural protection of 60m-high canal walls, and Eben Emael gave the impression of near-impregnability. Yet on 10 May just 7...