Prasat Ak Yum is situated on the southern bank of the West Baray, about 1 km from the baray’s southwest corner. This is not a popular temple destination. Because of its obscurity, many tuk tuk drivers and tour guides may not even know where it is located. A Glimpse into Pre-Angkor Cambodia. At first glance, the ruins of Prasat Ak Yum appear to be nothing more than a pile of rubbish. For this reason, many travelers and organized tours steer clear of this obscure monument. But for the serious Angkor enthusiast, Prasat Ak Yum is a must-see gateway into the pre-Angkorian period of the Khmer poeple.

Prasat Ak Yum was constructed sometime in the 8th century. It is the earliest known example of the ‘temple-mountain’. In essence, a temple-mountain is a mound or platform that is made of stone and/or other earthen materials. Typically, another structure is erected on top of the mound. In the case of Prasat Ak Yum, a prasat (tower) was erected on the mound. Prasat Ak Yum’s mound is a zigurrat, or step pyramid. A step pyramid is a structure made up of several layers, stacked on top of one another. Each ascending layer is smaller than the one before it.
The temple-mountain architectural formula of Prasat Ak Yum paved the way for the more famous temples of the Angkor period, most notably Angkor Wat. Ancient inscriptions located on some of the temple’s jamb stones reveal that the patron deity of Prasat Ak Yum was Gambhiresvara, the Hindu god of the depths.