KODA: Movable concrete house

KODA - coming in at 25 square metres or about 270 square feet - comes from Estonian designers   Kodasema who say the whole thing can be built in a day. It's built off-site from specially-develloped concrete panels, then craned into the location. It needs no foundations, just flat ground, and can be relocated again.
The structure allows in plenty of light and there are all kinds of eco-friendly features from filters to catch city dust and allergens, natural and non-toxic finishing materials, built-in adjustable LED lights, and various climate-controls to look after temperature and CO2 levels. KODA also has a digital door lock with a RFID entry system. Elsewhere, there are solar panels on the roof and excellent thermal insulation. There's an excellent interview with one of its creators at katus.eu

Best of all you don't have to go to Estonia to see it in the flesh as there is a prototype at the BRE Innovation Park in Watford (pictured below).

There's also a marvellous virtual tour of Koda so you can get a close look online.