Complex sentence: The massive sand dunes, known as Médanos, pread over an area of aproximately 30 kilometers long by 5 kilometers wide, and can reach 40 meters in height and are constantly transformed by the unrelenting wind.
Split into simpler sentences: The massive sand dunes, known as Médanos, spread over an area of approximately 30 kilometers long by 5 kilometers wide. They can reach 40 meters in height and are constantly transformed by the unrelenting wind.