Ladder

Ladders are stationary items that serve as a means of ascending or descending between different floors or levels. To ascend, interact with the area at the base of the ladder where it meets the ground. To descend, simply walk onto the ladder's hole. Most ladders in the game have a similar appearance and come in various materials, including:
Though they are rare there are trap door ladders, that you may only go down (Like some holes in the maze of lost souls), but not up, even by using a rope. You can tell these ladders from regular ones, because the ladder on the trap door ladder looks "sawed off" and you see only a small (unusable) ladder segment.