If you're heading east from Ubon to the Mekong, Khong Jiam is the first town you'll hit. It's a sleepy village (technically a so-called "district" of Ubon) notable for its pretty, flag-lined boardwalk along the Mekong River, which has food stalls and other vendors, and for its spectacular luxury hotel, the Tohsang. At the boardwalk, which overlooks the bend in the Mekong famous for its two colors (the uncharitable might call them yellow and brown), is a point where the River Mae Nam Moon, which begins in the Khao Yai forest and winds its way through much of Isan, past Ubon, Phimai, and Korat, empties into the Mekong. Here you can wander along the riverbank and take in the views or hire a local boatman to float you around for a bit; you can also enjoy a fresh fish lunch for pennies at one of the delicious open-air restaurants.