Quinta de Regaleira is a UNESCO World Heritage site designed by Carvalho Monteiro.
With the assistance of the Italian architect Luigi Manini, he designed the 4-hectare estate with its enigmatic buildings, believed to hide symbols related to alchemy, Masonry, the Knights Templar, and the Rosicrucians. The architecture of the palace evokes Roman, Gothic, Renaissance and Manueline architectural styles. The construction of the current estate commenced in 1904 and most of it was concluded by 1910.
The gardens are incredibly ornate. Set on a hillside, a multitude of fountains, grottoes, statues, caves, and ponds are connected both above ground via lovely paths and by a series of underground tunnels lit today by strings of Christmas lights. The grounds also include a chapel and an aquarium, built to look as if it naturally existed amongst the rock.