The most elaborate stupa is the 8th century Borobudur monument in Java, Indonesia. The upper rounded terrace with rows of bell-shaped stupas contained Buddha images symbolizing Arūpajhāna, the sphere of formlessness. The main stupa itself is empty, symbolizing complete perfection of enlightenment. The main stupa is the crown part of the monument, while the base is a pyramidal structure elaborated with galleries adorned with bas relief scenes derived from Buddhist texts and depicting the life of Gautama Buddha. Borobudur's unique and significant architecture has been acknowledged by UNESCO as the largest Buddhist monument in the world. It is also the world's largest Buddhist temple. as well as one of the greatest Buddhist monuments in the world.