Trakai Island Castle is a historic castle located on an island in Lake Galve in Trakai, Lithuania. The castle was originally built in the 14th century as a strategic defense fortress for the Grand Duchy of Lithuania. The castle has been destroyed and rebuilt multiple times throughout its history and has been used for various purposes, including as a residence for the Grand Duke of Lithuania, a prison, and a museum. Today, Trakai Island Castle is a popular tourist attraction and is recognized as an important part of Lithuania's cultural heritage. The castle is known for its picturesque location, unique architecture, and historical significance.