The first day of spring is just days away, and summer will quickly follow. The change to warm weather seasons has us dreaming of wiling away the sun-drenched days in nature with our kids. There's nothing more enchanting than a backyard, outdoor retreat, and these are some of our favorites. The NOA cabin, (pictured) is strikingly designed in the shape of a rhombic dodecahedron -- a form commonly found in nature as in honeycombs and some precious gemstones. This idyllic space makes for a perfect play space or cozy family cottage . These delightful hobbit homes are tiny hideouts that are handmade in the USA and big on backyard fun for your little Frodo. Designer Manuel Villa created the Habitable Polyhedron with new families in mind -- as a home away from home that could nestle in a back garden and serve as an idyllic getaway without leaving your property. The Knit Fort is an airy play space that expands and contracts , enabling kids to change the structure of their fort, thereby giving it a life of its own. This aptly named Dreaming Spires Willow Playhouse boasts a simply heavenly aesthetic in its graceful design and simplicity. It biodegrades over a matter of years, so it returns to the earth once your child has outgrown it. If you want to take building matters into your own hands, these 5 fantastic DIY forts will give you a big dose of pride every time you step inside to bask in your creation. The Froschköenig Treehouse takes treehouse design to new heights. Adults and kids alike would love to unwind in the serene lounging haven that gives inhabitants a bird's-eye view of the great outdoors.