George looks back over some favourite treehouses from Scotland to Sweden and Tuscany to Northumberland.

This time he focuses on how nature and architecture can work harmoniously together in the glorious world of cabins in the wild. There's a mountain-top ski lodge in Italy only accessible by helicopter; a hobbit-inspired cob house in Oxfordshire built for only ú150; and a concrete dome-home built under a man-made hill in a Texan hurricane valley. And George reflects on his own wilderness cabin that he built in the Sussex woodlands.