Base Jumps are an optional side activity in the second Grand Theft Auto IV episode The Ballad of Gay Tony. There are a total of 15 base jump locations around Liberty City that are required for 100% completion and for the Gone Down achievement on the Xbox 360 and the same trophy on the Playstation 3.
The first game in the Grand Theft Auto series to feature Parachutes and Base jumping, to a somewhat lesser extent, was 2004's Grand Theft Auto: San Andreas although the activity is not as structured as it is in the Ballad of Gay Tony and is not required for 100% completion.
In the minigame, there are locations found throughout the city where the player can find. If they are located, they are specified in three types of base jumps. Note that the base jumps have different difficulties but mostly remain simple. Target Jumps are the most common, and probably the easiest. Vehicle jumps sometimes tend to be the hardest because the jump must be made on a moving target. The vehicle target is a slow moving Flatbed (except in one base jump where it is a Marquis boat). Players should also be aware that when in helicopter and you have a parachute, sometimes it may not appear and you will just fall. However this can be fixed by selected the parachute on the D-Pad and click RT. This spawns the parachute on Luis' back and is ready for use. Overall, base-jumping and skydiving are great ways to see Liberty City from great heights. Base Jumps are also available in Multiplayer, although they only move you to the top of a tall building, rather than being airlifted above a target by helicopter.
The most common in the tall buildings of Algonquin. Are jumps that has checkpoints where the player must dive from. As usual, the landing point is on the streets below after the checkpoints are collected, where jumping from the Rotterdam Tower is one of the main Target Jumps where you land in the City Hall park.
The same as the target jumps but the landing point is a moving or a stationary vehicle. The National Newark Building is a Vehicle Jump.
Also the same with the mechanics of target and vehicle jumps but the starting point is in a helicopter. The LC24 Tower is one of the Helicopter Jumps.