A short journey up the Prahova Valley from Ploiesti, Peles Castle in Sinaia is one of Europes most beautiful royal palaces, a fairytale Neo-Renaissance residence built for King Carol I amid forested mountains. Its lavish interiors of carved wood, stained glass and art are a highlight of any visit to Romania. Ticketed guided tours lead through the opulent rooms, making the castle a spectacular and popular excursion from the city into the mountains.