Treehouses have grown into serious architectural projects that turn a stay into part of the trip itself. Designers now treat treetop structures as places for comfort, creativity, and quieter living.

Glamping that's good for you?

Pete Nelson of Nelson Treehouse & Supply in Fall City has built almost 400 treehouses across the world, starting when he was 7 with his dad. Now 62, he is something of a grandfather and ambassador to ...