Zipline

The Zipline is the name of a lift in the Call of Duty: World at War Zombies map Shi No Numa and of the actual ziplines in Call of Duty: Black Ops multiplayer map Kowloon and Zombies map Call of the Dead.

Shi No Numa
The zipline in Shi No Numa was the first to appear in the Call of Duty series, both in zombies and multiplayer. To be used, it has to be activated using a Control Panel outside of the Doctor's Quarters. Once activated, it goes to the Doctor's Quarters, where it costs 1500 points to ride up to the Warning Room of the main building. While moving, the zipline can kill zombies and down players. The Zipline offers a quick escape when the zombie horde becomes overwhelming. Players use it to exit the doctors quarters or the second floor of the main building. Players should be careful if there are more than two on it since players might get pushed off. This is a great escape for anyone who needs it.

Call of the Dead
The normal zipline appears in Call of the Dead. One of the ziplines appears at the top of the first ship, where the power switch is. Players can take it from the ship to the coast (spawn area). Zombies can also use it including George A. Romero, so it isn't as useful as its Shi No Numa counterpart. However the fact that it can be used at any time and doesn't cost any points could balance this out. Unlike Kowloon, the player can use their gun while on the zipline, without the ability to reload or aim down the sights. There is also a zipline running from the top of the lighthouse to the ship, but this is initially blocked. To unblock this zipline, one must unblock the path leading from the lighthouse to the ship by buying the boat. With this zipline, if the player just walks toward the zipline instead of jumping, they will not use the zipline, but instead fall all the way to the base of the lighthouse. This will down the player instantly unless he has PhD Flopper, or if he has full health with Juggernog. The zombies will all take the zipline, giving you a few seconds to prepare.

The zipline has no prompt on how to use it. Simply jump towards it to use it.

Multiplayer
It is only included in only one multiplayer map, Kowloon. It has one small zipline and one big zipline, both connected to one building. Each zipline connects to the other team's spawn point and they can only be used from the higher point. The higher point is located in a building in the middle of the map, making it a highly contested area.

It should be noted that the player is very vulnerable to enemy fire, so the zipline should only be used when there are no enemies around.

Trivia

 * In Call of Duty: Black Ops, if a Semtex or tomahawk is thrown at a player going down the zipline, it will often float in the air or come back to the person who threw it.
 * If the match finishes and the player is on the zipline, they will continue to move down the zipline, and once the zipline has reached the end, they will drop to the ground very slowly.
 * In Call of the Dead, if one person is in Spectator Mode and watches a player go down the zipline the player's hand does not appear on the gun and the gun appears as if it is floating. This is most noticeable on small weapons, such as the Ray Gun or PM63.
 * While using a zipline in Call of the Dead with a Dual Wield weapon, only the right one appears on screen, but both can be fired.
 * The sickle, when paired with the ballistic knife, floats in the air when the player rides down the zipline.
 * Only in Call of the Dead it is possible to hold the Death Machine one-handed when going down the zipline.
 * If a pump-action weapon is fired while riding it, it will pump as normally, just with no hand pumping it. The same happens with the bolt action rifles, the L96A1, and the Scavenger.
 * If the M72 LAW is fired while on the zipline, the player will still aim down the sights before firing, unlike every other weapon, which are hip fired.
 * According to the PC Files for Call of Duty: Black Ops II, there was originally going to be a zipline in Zombies.

http://www.youtube.com/watch?v=C7QSBIFC3h8