Heidelberg Castle is an old reddish-brown castle, which is the symbol of Heidelberg Castle. The castle is situated on the wooded Koenigsstuhl on the banks of the Neka River, the site of the Palace of the Elected Emperor. The castle is mainly built of the red-brown sandstone of the Neica River. The inner structure of the castle is complex, including defensive fortifications, living rooms and palaces. Founded in the 13th century, it took 400 years to complete. Due to the changing architectural style, a wonderful mixture of Gothic, Baroque and Renaissance styles has been formed, which is the representative works of German Renaissance architecture. In the 17th century, the castle was destroyed twice by the French. The family of the emperor-elect moved to Mannheim. Some of the abandoned castles were later restored and rebuilt. Only at the end of the 19th century did the main buildings regain their original appearance and be able to use.