A church built on top of an ancient volcanic plug. Hard to imagine how they did that, but building things on impossible locations is one of those challenges that has to be met, particularly where religious symbolism is involved.
The stairs to climb up to the top are not as rigorous as you might think (there's only 200 of them if I recall) - it's worth your effort to make the climb.
Once there, if you're lucky enough to have the place to yourself as we were, it's quite a special experience spending a little time there meditating and marvelling at how all this was done - and why.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.