Operation Market Garden was an allied plan to advance into the Netherlands and secure bridges that would enable them to push through north Germany and on to Berlin avoiding the heavily fortified Siegfried line.
Thousands of paratroopers were parachuted behind enemy lines on 17th September 1944, the first day of the operation. Each group were dropped in proximity to one of the bridges, their mission to secure it as quickly as possible. Most bridges were secured as planned but the bridge at Nijmegen bridge was not secured by the Americans as scheduled. The bridge at Nijmegen was vital because it was the route that reinforcements would take to relive the British force that held the northern end of the bridge at Arnhem.
The continued delay in taking the bridge at Nijmegen gave the Germans time to mount a counter-offensive and although the bridge was held it was impossible to cross. The British troops holding the northern end of the bridge at Arnhem were isolated behind enemy lines. Although they fought bravely, without reinforcements they were no match for the Germans who systematically destroyed the houses the British were hiding in.
On 26th September the mission was declared a failure.