If you saw thousands of sparkling blue pools nestled between sand dunes, stretching far beyond the horizon, you could be forgiven for thinking you were momentarily hallucinating. But Lençóis Maranhenses National Park, located in the Brazilian state of Maranhão, is no mirage. The park's white sand dunes and shimmering lagoons sprawl across 580 square miles of the northern Atlantic coast, near the Amazon Basin.

But first, how do they even occur? Well two rivers run through the national park, which deposit sediment as they flow toward the Atlantic Ocean. It is this sediment that actually creates the majestic dunes that give Lençóis Maranhenses National Park its name, however the rivers are not soley responsible. During the region's dry season, winds from the Atlantic push inland, picking up the sand and tossing it into rolling dunes.

This vast amount of sand makes Lençóis Maranhenses National Park look like a desert, but the area actually receives too much rain to qualify as a typical desert. The area can receive more than 50 inches of rain per year, most of which will fall in torrential rainstorms from January to June. Thanks to the wet season's downpour, the lagoons in the park reach their peak in July and remain full until September. Some of the pools — which come in varying shades of green, blue, and black – can be several feet deep. Lagoa Azul and Lagoa Bonita are two of the biggest lagoons in the park.

But, what stops these collections of fresh water from being absorbed into the earth? A layer of rock hidden beneath the sand stops the water from percolating, instead capturing the rainfall to form countless stunning pockets.

Though the national park is not a true desert, it does share some of the harsh environmental characteristics that make it difficult for wildlife to thrive here. A few crafty species of fish, however, manage to survive in the lagoons during the wet season. One predatory species known as the wolf fish or tiger fish does so by burrowing into the few moist spots left during the dry season. The fish will then remerge when the park enters its wet season and the pools refill.

While there are a handful of small towns that serve as entry points to this sandy paradise, getting to Lençóis Maranhenses National Park takes a little work. The park does not have any roads for direct access, and most vehicles are not allowed in the park. But you can hop on a plane from the small town of Barreirinhas and take a scenic flight over the park. Day trip tours also regularly leave from Barreirinhas.

Despite the remote location, the journey is worth it, rewarding you with incredible views over this insanely unique expanse.