Operation Eisenhammer (German; in English Operation Iron Hammer) was a planned strategic bombing operation against power generators near Moscow and Gorky in the Soviet Union which was planned by Nazi Germany during World War II but eventually abandoned. To accomplish the goal Mistel long range bombers were to be employed. To destroy water turbines special floating mines called Sommerballon ("summer balloon") were to be dropped into the water and then pulled by the current straight into the turbines.