Quinta da Regaleira

Quinta da Regaleira is an estate located near the historic center of Sintra, Portugal. It is classified as a World Heritage Site by UNESCO within the "Cultural Landscape of Sintra". Along with other palaces in this area (such as the Pena, Monserrate and Seteais palaces), it is one of the principal tourist attractions of Sintra. It consists of a romantic palace and chapel, and a luxurious park featuring lakes, grottoes, wells, benches, fountains, and a vast array of exquisite constructions. The palace is also known as "Palace of Monteiro the Millionaire", from the nickname of its first owner, António Augusto Carvalho Monteiro.

It is an amazing place that cannot be described justly. You can read more about it on Wikipedia.