The Quinta da Regaleira is a vast estate in Portugal featuring a castle built by Afonso Henriques, the first king of Portugal after the conquest of Lisbon in 1147. After almost a millenium, the property came into the possession of António Augusto Carvalho Monteiro, a wealthy entomologist, who had it transformed with features associated with Masonry, the Knights Templar, and the Rosicrucians. Prominent among these are a pair of “initiation wells,” one in the shape of an inverted tower that burrows deep into the earth. The BBC made a fascinating video presentation that you can see here:
And here’s a basic overview from Ancient-Origins.net:
Thanks Soror Hypatia for the tip!