Erwang Temple — the Temple of the Two Kings — stands on a wooded hillside directly above the Dujiangyan irrigation works, connected to the site by a covered walkway and suspension bridge. It was built to honour Li Bing and his son Er Lang, the father-and-son engineers credited with designing and supervising the irrigation system. The original structure dates to the fourth or fifth century; the current buildings are Qing-dynasty reconstructions.
The main hall contains statues of both men rendered in the style of Daoist immortals, which is more or less how local people came to regard them — deified engineers whose practical achievement kept millions fed for centuries. Stone inscriptions around the complex record the ancient hydraulic principles for managing the river, including a six-character formula attributed to Li Bing himself.
The temple grounds are peaceful, with good views down to the river and the fish-mouth island below. A path through the bamboo continues up the hill to a gate and further viewpoints. Admission to the irrigation park covers Erwang Temple; it can also be reached independently from the back road for free if you want to visit without paying full site admission.