Sitting above the rooftops in The Netherlands, the Mirror Mirror Roof House puts all other tree houses to shame. Like its name implies, the cubed roof extension is clad in a mirrored glass, reflecting the landscape around it and making it almost disappear into the background. The double-height interior is completely sheathed in sheets of natural pinewood, housing an office and a floating steel bedroom. Large openings on every wall not only allow in plenty of sunlight but also provide continuous views of the surround treetops. Not too shabby for a 12-year-old boy.