Wan Ok Phansa
The day is celebrated in Isan by illuminated boat processions ( "lai ruea fai" , "lai huea fai" ) , notably in Nakhon Phanom Province on the Mekong and in Ubon Ratchathani on the Mun River . 
<triplet> Mekong <subj> Mun River <obj> tributary <triplet> Mun River <subj> Mekong <obj> mouth of the watercourse