Developer SledgeHammer Games of Call Of Duty: Advanced Warfare has made the game’s Atlas Gorge DLC map free for all players on all platforms.
— Sledgehammer Games (@SHGames) May 23, 2016
The map was originally released for both the Pro and Limited edition of the game during its launch in 2014. It was also later released as a $4.99 download for players that did not purchase either of those editions of the game.
The official description of the map states, “Atlas Gorge re-envisions the fan-favorite Call of Duty 4: Modern Warfare map Pipeline. The Atlas Corporation has commandeered the world’s largest power source, the Three Gorges Dam in central China, whose sinister backdrop creates a gripping setting for multiplayer battle. Combatants will navigate the shadows, explore the map’s new verticality empowered by exoskeleton technology, and control a map-based turret scorestreak that overlooks the dam and helps to keep enemies at bay.”
Advanced Warfare was originally launched in November of 2014. The next entry in the Call of Duty franchise is slated for a November 2016 launch. You can read more about Infinite Warfare and its recently confirmed Zombies mode here