The Old Spanish Church is a ruined building in Crystal Cove that may have been built at the time of the conquistadors.
Scooby-Doo! Mystery Incorporated
Professor Pericles and Scooby-Doo visited it, supposedly for Pericles to get pewter for his antidote, but actually for him to steal a shipping manifest that once belonged to an old Spanish ship. (Where Walks Aphrodite)
Both the old Mystery Incorporated and the new one had visited there and found clues to the cursed treasure of the conquistadors hidden somewhere in or near Crystal Cove. The old Mystery Inc. was threatened and driven out of town after this, and Cassidy Williams warned the new team that it could happen to them. (Pawn of Shadows)