Minecraft wiki entry for Straight_Staircase, associated text: Stronghold Straight Staircases are naturally generated components of strongholds. They are composed of stone bricks, mossy stone bricks, cracked stone bricks, and cobblestone stairs, with the possibility of containing wood or iron doors, iron bars and stone buttons. The variance of bricks, including infested stone bricks, is random in all layers yet with a notable predominance of Stone Bricks. The top and bottom entrances to the staircase can be any combination of four entrance variants. They can either be completely open, be surrounded by iron bars, have a wooden door entrance, or an iron door entrance, with one or two buttons. When the door variants are present, the doors are flush with the outside face of the staircase on the bottom, and the inside face on the top. When iron bar variant is in place, the bars can either be located in the same row that a door would be, or could be located one row further from the staircase.