From Introduction:
The gallery is an adventure add-on that aDM can place nearly anywhere. The gallery is a small, crumbling building, long abandoned. Anyone who enters and learns its secrets discovers a fantastic new gateway to adventure.
The Ruin
The gallery is located in a once-stately, now ruined mausoleum. The gallery was built to honor the fallen hero Rexus, and is erected on the spot where he was slain in battle. The ruin was built so long ago that no one remembers who Rexus was anymore, or why he is so honored. The ruin is overgrown, and few if any pay the slightest bit of attention to its presence. If anyone enters the ruin, refer to the descriptions of the individual areas below.