TBy late April, 1941, the British, Commonwealth and Greek forces were in full retreat to the Peloponnesian peninsula where the British navy was already evacuating thousands of troops to Crete off the east coast. In order to reach the Peloponnese, the evacuating troops had to cross over the narrow Isthmus of Corinth which was cut by a canal that linked the Gulf of Corinth and the Aegean Sea.
At dawn on 26 April 1941, the 2nd Fallschirmjaeger (parachute) Regiment landed on both sides of the canal to seize the bridges in order to cut off the withdrawal and open up an avenue for the pursuing panzers to cross the canal. The parachute landings surprised the defending Australian battalion, but by the time the Germans managed to get organized and find their weapons (Fallshirmjaeger parachuted unarmed and gathered their weapons from canisters parachuted separately), the Australian infantry and British Matilda tanks were already counterattacking. However, German Stuka dive bombers broke up the attacks, and within the hour there was hand to hand fighting on both sides of the highway bridge and foot bridge.
About 0800, the bridge exploded. There are two theories: 1. The Australians detonated the charges (the simple and most likely theory) and 2. The German paratroops seized the bridge, cleared the explosives, cut the wires, and a rogue shell fired by a Kiwi artillery piece eight miles away set the explosives off (an account given by a German officer who would have suffered severe repercussions for allowing the bridge to be destroyed. Needless to say this account is most favored by German historians and airborne enthusiasts).
You, intelligent reader, judge for yourself.
In any case the bridge was destroyed, and the 2nd FJ took extensive casualties. The 1st SS Leibstandarte Division was delayed crossing the canal, which allowed another 22,000 Allioed troops to evacuate from Nafplio. The cut off British rearguard, the 4th New Zealand Bde retreated to Megara, near Athens, and was evacuated with great difficulty by the British navy the next day.