From the Introduction:
The characters on this adventure are pilgrims, all seeking the knowledge that can be gained from an Oracle that lives high up in the Cathedral. The Cathedral in Santa Cora stretches as high as the clouds and beyond, and walking the millions of steps up into the clouds is considered a form of worship and a holy endeavor.
To reach the Oracle requires a trek equivalent to climbing several mountains, and most pilgrims turn back. Even if the pilgrims are hardy enough to climb the Cathedral there is the issue of the thousands of monks, hermits, stylites, ascetics, zealots, mystery cults, priests, paladins, cenobites, stoics, sages, saints, fakirs, holy fools, desert mothers, demianites, matrisses, nuns, templars, sōhei, mendicants, eremitics,
barefoot seekers of truth, and celestines. Each god or goddess of light has a temple within the mighty Cathedral, and to pass up the Cathedral it is necessary to pass through most of them. Some might be bypassed or passed through with naught but a simple tithe or show of devotion.
...other holy places are not so easy to pass through.
This is a dungeon crawl, but ascending vertically and with a ‘holy’ theme.