- "Hydroelectric power plant in the heart of Pakistan. Fast, close quarters fights on each lane. Beware of the spillway."
- — Map description
Hydro is a multiplayer map included in the Call of Duty: Black Ops II downloadable content pack Revolution. It takes place on a large hydroelectric dam facility set in Pakistan, which contains multiple choke points.
At around the halfway point of each round, a Pakistani announcer is heard via the speakers. After a few seconds, the spillway in the middle of the map is filled with water for a small period of time. The rushing water will kill anyone and anything (including scorestreaks and equipment).
- The announcer says "The water system has been closed" in Urdu.
- If the round time limit is set to unlimited, the spillway is never flooded.
- If the player throws a Smoke Grenade at the spillway, no smoke will be emitted.
- If the player plants the Assault Shield in the calm water, they can take cover behind it and survive the flood.
- Hunter Killer Drones can fly through the flood.
- Near the walkways, there are windows. If one runs fast enough, they can potentially Dive to Prone and be "on top" of the window.