The waterfalls of Tad Kuang Xi or Xé are great and very impressive. Tad Xé is not permanent and worth seeing anyway, especially during the rainy season when the water rushes furiously. Young monks from other places coming there to bathe all dressed.
The Pak Ou cave will also satisfy your curiosity and you will be amazed by the beauty of this worship place.
In addition, many small surrounding villages are worth a visit. Often accessible via river, they offer an extensive and interesting view on the business of manufacturing in the region: Lao Lao whiskey, the art of weaving, handmade paper...
A region rich in discoveries of all kinds...