Taman Sari in Yogyakarta is a former water complex containing an artificial lake, islands, the royal bath, a mosque, underground passages and bridges. It was also part of the defense system of the palace in Yogyakarta, but above all it was a place of rest for the sultan and his court. Little is left today of those objects. The lake does not exist; the whole area is densely covered with buildings. Well worth a visit are still existing fragments of the complex: bathing area called Water Castle, and the circular structure known as a Gumuling Well. Access to the latter is possible only through an underground tunnel.