Aerial drone view of Pena Palace, UNESCO World Heritage Site, a romanticist castle in the Sintra mountains, Portugal, Europe

photography horizontal color image travel destinations travel outdoors sunset dusk no people portugal europe pena palace palace building architecture unesco world heritage site castle fortress built structure sintra mountains mountain clear sky tree nature drone point of view aerial view trees travel destination tourist destination tourist destinations sundown evening twilight outdoor outside nobody no one no person mountains fort forts fortresses past history historic archaeological archaeology ruin ruins old ruin old ruins castles fortified fortification historical buildings