Basilica of the Dune-Cursed Messiah

From publisher blurb:

We thought we would die out here, to be lost beneath the shifting sands of this desert, when the ranger spotted a well. Of course, there was no water in it, but our voices echoes oddly. When we took a risk and climbed down the shaft, we discovered an enormous temple full of books and scrolls! Millennia of forgotten knowledge. Of course, no great wealth goes unguarded...

This is a system-agnostic dungeon designed to slot easily into whatever kind of campaign you might be running. Use it as a random wilderness encounter, a challenge between your party and that healing break they're so eager for, or the start to a dragon nemesis campaign.