One of the items I put in the "bazaar bargains" deck that lower-level PCs could draw from in the Arneson Memorial gameday event was an intelligent door that could detect secret doors. Using this, the party managed to find and descend one of the staircases in the pillars! Whether they looked for this because I described how strangely massive the pillars were, or whether it was because someone heard me talking about it online, I cannot say :)