Absolutely beautiful Sand dunes in the mountains, it actually smells like an ocean beach and makes you feel like your on another world. The Dunes are 30 square miles and you can camp anywhere in them with a free permit available at the visitor center, just have to hike in past the first ridge aka the day use area. It's tent camping only, and no pets are allowed in the back country dunes. You also need to pack everything you need in with you and leave no trace. The winds blow often and hard, moving enough Sand to cover you tracks in minutes. The views of the sky and stars are absolutely mesmerizing, one of the most beautiful Sand fields in the world. The creek that runs through the day use area can fluctuate in size daily, it wasn't high when we were there, but it was still flowing half way through the day use area. A must see destination if your in the San Luis Valley.