When you first think about the words concrete house, you might imagine a cold, sterile environment, perhaps something similar to a prison. If that's the case, this one story house designed by architecture studio A-cero will likely change your mind. Located on the outskirts of Madrid, Concrete House II features a façade that boasts a spectacular view of the whole house. The first impression that visitors usually get is that the building seems to be hidden between concrete walls and ramps that extend up to the roof. Upon further inspection, they find a vegetation area that climbs towards the sky! The back of the house opens up towards the garden where the lounge, dining room, library, study, and bedrooms are found. Outside, the plot includes an elegant garden and small lake, while the roof features solar panels and a renewable energy system.