Heidelberg Castle is a ruined castle located in Heidelberg, Germany. It was built in the 14th century and served as a residence for the Electors of the Palatinate. The castle is situated on a hill above the city, providing a panoramic view of the surrounding countryside. Throughout its history, the castle has undergone several additions and renovations, with the most significant being in the Renaissance style. Today, the castle is a popular tourist attraction, attracting visitors from all over the world. Visitors can tour the castle's grounds, including the Great Hall, the Knights' Hall, the Garden House, and the courtyard. The castle is also known for its stunning views of the city and the Neckar River.