The House of Spiritual Retreat (Casa De Retiro Spiritual), which can be described as an "extreme" homes, was designed by architect, Emilio Ambasz.
The odd-looking home has been dubbed the "Book House" and for good reason, as the only two walls above the ground make the structure look like a giant, open book. Climb down one of the two visible staircases and you'll find the actual house which is hidden underground.
Implications - As urban areas increase in population, living areas are dramatically decreasing in size. This leaves consumers in cramped conditions that offer them little privacy. Architectural firms can cater to these cramped citizens by designing living structures that prioritize open space and privacy.