La ermita rupestre de la Espelunga
Espelunga (also written espelunca) comes from the latin spelunca, and is a noun which -- as you might guess from our English word "spelunk" -- means cave. And, since rupestre is an adjective that also means "cave" (as in cave dwelling, cave drawings, etc.), the literal translation of this place would be: "Cave hermitage of the cave."
It's in the mountains to the east of Aínsa, in Huesca, a good 45 minute to hour's walk up from the Monasterio de San Victorián, which is the allegedly the oldest monastery in Spain (from the start of the 6th century).