Visiting Las Pailas (or Las Paylas) in Luquillo, Puerto Rico, is one of the most authentic and enjoyable experiences for connecting with nature. Las Pailas is a series of natural water slides formed by the Pitaya River, where the water has worn away the rocks, creating spectacular cascades. Natural Water Slides: You will find two main slides; one shorter and gentler for warming up, and the other longer and faster, leading to a pool of turquoise waters. A dip in the river, swimming in the best part of the river.