Some might say that tree houses are just for kids, but the architects of these innovative homes might beg to differ.
1. The glass-enclosed tree
The architect of this house created vertical windows that enclose the tree trunks.
2. Spiral staircase
This spiral staircase in Hector, New York winds around a tree trunk.
3. The living room tree
Courtesy of Pazarquitectura
This cement house in Guatemala has a tree growing through the living room.
4. Tree stump house
Courtesy of the University of Washington Libraries Digital Collections
This little house was made from the stump of a cedar tree.
5. The tree-friendly deck
Courtesy of munozarquitectos
This architects of this house in Mexico preserved dozens of trees on the property, including the many trees growing where they wanted to put a pool deck.
6. Beachfront tree house
Courtesy of CoolTreeHouse
The owners of this treehouse on Anna Maria Island in Florida are fighting a zoning battle to keep it.
7. Courtyard tree
Courtesy of Hufft
Even though the house wasn't planned around this small courtyard tree, we like the way a little outdoor space was tucked into the center of the house.
8. Inspired by God
Flickr: Frank Kehren
This house in Tennessee incorporates seven trees. It is currently closed to the public.
9. A-frame house
Courtesy of OnDesign
A house in Tokyo has trees growing though the edge of the roof.
10. The fig tree house
Courtesy of EmailFlyers
The foundation of this 1919 house in Pasadena was built around the roots of a Moreton Bay fig tree thought to be hundreds of years old.
Courtesy of The Redwoods Treehouse
It's not a house, but we couldn't resist including this other-worldly pod built around a redwood tree. It's an event venue in New Zealand that holds up to 30 guests.