The black-out in southern Sweden and eastern Denmark, September 23, 2003.

At midday on Tuesday september 23 2003, the Nordic power system experienced the most severe disturbance in 20 years. The southern part of Sweden and the eastern part of Denmark, including its capital city of Copenhagen, were blacked-out. The cause was a close coincidence of severe faults leading to a burden on the system far beyond the contingencies regarded in normal system design and operating security standards