Nong Khai is 50km north of Udon Thani, Thailand, a former US military base during the Vietnam War. I went from Udon to Nong Khai and headed straight for the Mekong. On the street by the water is a huge market called Smuggler's Market. They sell knick-knacks, T-shirts, religious items, and silks. It is acceptable to negotiate prices with vendors.
After that, head for the Sala Keo Kou sculpture garden. It was built in honor of a Buddhist monk from Laos. The sculptures are incredible!