Borobudur is an exquisite monument in Central Java, Indonesia, that visually represents the Buddhist cosmology with the compilation of the world of the kāma-dhātu, the rūpa-dhātu, and the ārūpya-dhātu. The pilgrims who come to Borobudur will go up each terrace of Borobudur to the right, searching for the truth, and experiencing the trip of Sudhana by themselves. Borobudur indicates Indonesia's architectural technology and its supporting abilities such as mathematics, engineering, construction technology, and arts were assembled as one monument in the 8th and 9th centuries. Since the knowledge and skills that can construct a huge monument like Borobudur cannot be acquired in a short period of time, it is likely to say that the Śailendra dynasty should have gotten support and cooperation from the Sanjaya dynasty. Since it is neither a stupa nor a temple, it is argued that Borobudur was designed as a mandala of Esoteric Buddhism. However, none of the elements of Vajrayana Buddhism can be identified in Borobudur. Rather than a mandala, Borobudur must have been built to show off the authority of the Śailendra and the Sanjaya dynasties and to make people learn Buddhist doctrine through its reliefs. Borobudur shows the way of how Buddhism embodies its philosophy as a monument and how it could have flourished in a short period of time on the back of the power of the kingdom.