The Ruins of the Lighthouse of the Town
Map of Si Mahosot ancient town show the location of The Ruins of the Lighthouse of the Town 
The rectangular laterite and brick base (The ruins No.1), is presumed to have been the remains of a lighthouse, in which a square laterite block with a hole has been foun in situ. It was likely a plinth for erecting a flag pole or a flaming torch at the top. Its location is near a particular point where the Si Mahosot Town’s ‘linking ditch’ joins the ‘northern ditch’ which is in proximity to a waterway flowing into the sea. Therefore, the flag or the torchlight at the top of the pole would be clearly recognized by men on board the boats or junks sailing to the town, between the late 6th and 12th centuries CE.
Depicting scene of ancient trade of Si Mahosot people
Persian ceramics found by archaeological excavation at the ruined No.46
Evidences of ancient trading with seafarers display at Prachin Buri National Museum
According to the Royal Gazette no 52, dated March 16th, 1935, The Fine Arts Department announced that this monument has been listed as the nation’s historic site.