In the 19th century Sintra became the first centre of European Romantic architecture. Ferdinand II turned a ruined monastery into a castle where this new sensitivity was displayed in the use of Gothic, Egyptian, Moorish and Renaissance elements and in the creation of a park blending local and exotic species of trees. Other fine dwellings, built along the same lines in the surrounding serra , created a unique combination of parks and gardens which influenced the development of landscape architecture throughout Europe.

Źródło: World Heritage Convention
http://whc.unesco.org/en/list/723