Lençóis Maranhenses National Park is a unique landscape of vast, undulating sand dunes interspersed with clear, rainwater lagoons. The best time to visit is during the rainy season (typically May to September) when the lagoons are full. Accessibility can be challenging, with sandy terrain requiring 4x4 vehicles; tours are highly recommended, especially for first-time visitors. Solo exploration is possible but requires careful planning and navigation skills. Guided tours offer valuable insights and ensure safety. Costs vary depending on the tour operator and duration, but expect to spend a moderate amount, including transportation and accommodation in nearby towns like Barreirinhas. A typical visit lasts 2-3 days to fully experience the park's highlights, including swimming in the lagoons and trekking across the dunes. Be aware that during the dry season, some lagoons may dry up completely.