Complex sentence: It is classified as a World Heritage Site by UNESCO within the "Cultural Landscape of Sintra", and along with other palaces in this area (such as the Pena Palace and Monserrate Palace), it is one of the principal tourist attractions of Sintra.
Split into simpler sentences: 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 Palace and Monserrate Palace), it is one of the principal tourist attractions of Sintra.