The Fine Arts Department has begun excavating a 1000+ year old Khmer bridge in the old city of Nong Han Luang

Thai language video, no subtitles available  

Plenty of speculation when the bridge was built. 

There's even a suggestion that it's not a bridge, it's a dam to hold water for farming.

I read one article which suggested that it was disassembled from another location and reassembled at its present location.