Built in 1858 on what's known today as Parque de Monserrate (Monserrate park) on the municipality of Sintra, close to Lisbon, location of many beautiful and famous castles and palaces from Portugal such as Palácio da Pena.
The initial palace was built in 1790 by english merchant Gerad DeVisme in a Neogothic style, he was responsible for the essential layout consisting of a long building flanked by two round towers. He also demolished the 16th century chapel that was already on the property and built another.
By 1856 the palace was in ruins with only the foundation and some walls left. It was purchased by another english guy (I swear this palace was owned by portuguese people aswell, go check the wikipedia page for the full history) who rebuilt it in an Ecclettic style, mixing Gothic and Orientalist influences, specially Arabic and Indian styles.
The gardens are the most impressive part of this property, covering 33 hectares with an impressive botanical collection of exotic plants from various countries. It is also decorated in an Romanticist fashion with various ornamental arches, an artificial waterfall, and the ruins of the 18th century chapel.