Aerial view of Khlong Samrohng, a 55 km canal spanning Samut Prakan and Chachengsao provinces, originally developed during King Ramathibodi II's reign in Ayutthaya for maritime trade and travel. However, evidence suggests it may have existed before the Ayutthaya period and could have been dug as a military route from Angkor Thom (fig.), to the Chao Phraya River basin.