The Quinta da Regaleira is a beautiful estate located in Sintra, Portugal. It is a unique and fascinating site that combines Gothic and Renaissance architectural styles, and is known for its beautiful gardens and hidden underground tunnels.

The estate was built in the early 20th century by a wealthy Brazilian businessman, António Augusto Carvalho Monteiro, who was interested in the occult and the symbolism of the Knights Templar. The result is a complex of buildings, gardens, and grottoes that are rich in symbolism and mystery.

The highlight of the Quinta da Regaleira is the Initiatic Well, a 27-meter-deep spiral staircase that leads to underground caves and tunnels. The well is said to symbolize the journey of the initiate into the mysteries of the occult.

The gardens are also a must-see, they are filled with sculptures, fountains, and secret grottoes. Visitors can explore the palace, the chapel, the towers and the lakes, all surrounded by lush vegetation.

Overall, the Quinta da Regaleira is a unique and fascinating site that should not be missed when visiting Sintra. It's a perfect combination of history, architecture, and nature that will leave visitors with a memorable experience.