Welcome to Retalhuleu
Retalhuleu, or Reu (ray-oo) as it's known to most Guatemalans, is a small town packed with fine old buildings. In the early 20th century it was an important trading center, with a railway that linked the cotton-producing lowlands to the steamer trade on the Pacific coast. Its best days might be behind it, but the area around the plaza is worth exploring, along with the atmospherically abandoned and overgrown train station.
Most people visit for access to the Maya ruins at Takalik Abaj, but if you're up for some serious downtime, a couple of world-class fun parks are just down the road.