Pillar: A common sight in any dungeon, pillars and columns give support to ceilings. The larger the room, the more likely it has pillars. As a rule of thumb, the deeper in the dungeon a room is, the thicker the pillars need to be to support the overhead weight. Pillars tend to be polished and often have carvings, paintings, or inscriptions upon them.
Slender Pillar: These pillars are only a foot or two across, so they don’t occupy a whole square. A creature standing in the same square as a slender pillar gains a +2 cover bonus to Armor Class and a +1 cover bonus on Reflex saves (these bonuses don’t stack with cover bonuses from other sources). The presence of a slender pillar does not otherwise affect a creature’s fighting space, because it’s assumed that the creature is using the pillar to its advantage when it can. A typical slender pillar has AC 4, hardness 8, and 250 hit points.
Wide Pillar: These pillars take up an entire square and provide cover to anyone behind them. They have AC 3, hardness 8, and 900 hit points. A DC 20 Climb check is sufficient to climb most pillars; the DC increases to 25 for polished or unusually slick ones.