The legendary city of the gods has been taken over by Aldrich, Devourer of Gods. Once radiant with sunlight, it is now entirely dark due to the absence of Dark Sun Gwyndolin. The main cathedral is overrun with Deacons of the Deep, slime creatures, and a rare, spider-like Deep Accursed which hides on the ceiling near the golden double doors. The rest of Anor Londo as seen in Dark Souls I is inaccessible due to collapsed debris which blocks the stairwell. The body of the Giant Blacksmith can be found slumped over his old anvil and holding the Giant's Coal.
Company Captain Yorshka, leader of the Darkmoon covenant, can be found on the tower where the building containing the Painted World of Ariamis used to be. To reach her, you must walk off the ledge of the spinning staircase and run along an invisible path, similar to the invisible paths within the Crystal Cave of Dark Souls I. Simply run in a straight line while in midair until you are even with the "entrance" to the tower, then face the tower and run straight onto it.
The area where Ornstein and Smough were fought in Dark Souls I is now covered in waste and inhabited by Aldrich, Devourer of Gods. Prior to the arrival of Aldrich, Pontiff Sulyvahn trapped an infirmed Gwyndolin here to be devoured by Aldrich. By the time Aldrich is confronted by the player, it appears that Gwyndolin has been half-eaten and is under the control of Aldrich.
Surprisingly, the elevators leading up to Gwynevere's chamber are still operational, though the chamber itself is decrepit and empty with the exception of the Sun Princess Ring. If you have followed Ringfinger Leonhard's storyline, and he has killed Rosaria, it is possible to invade him using the Back Eye Orb in this area to reclaim Rosaria's Soul.
Also accessible in Anor Londo is the Darkmoon Tomb, which is hidden behind an illusory statue of Gwyn at the bottom of the spinning staircase. The Darkmoon Tomb used to be the location of Gwyndolin and and the Darkmoon covenant prior to the events of Dark Souls III. The Darkmoon Tomb houses the honorary tomb of Gwyn, and is the home of a significant event in the stories of Yuria of Londor and Anri of Astora.