COMPLEX ECOSYSTEM: The dunes in Lençóis Maranhenses National Park, which you can see in the tan section of this photo, are surrounded by ocean and forests. Image by NASA Earth Observatory/Michala Garrison. Image by NASA Earth Observatory/Michala Garrison. Satellite imagery also helps explain the park’s name: In Portuguese, Lençóis Maranhenses means “the bedsheets of Maranhão”—an apt description of how these dunes and lakes appear from the sky. AdvertisementLead image: NASA Earth Observatory / Michala Garrison