09/18/2012 02:15 pm ET Updated Dec 06, 2017

Watch: See-Through Bathroom Provides Daylight to City Apartment

When Miguel Angel and Elodie Grammont bought their apartment in Barcelona's Eixample district, it was divided into small rooms, a relic of 18th century design. The two architects -- co-founders of Miel Arquitectos -- knew they wanted to open it to let more daylight in, but rather than simply creating an open loft space they redefined the rules of privacy. "When you don't need the toilet so closed or the bathroom isolated from the other things is when you find a way to live inside," explains Miguel.

To let daylight into both their bathroom and bedroom, they left the bathroom open to the living room (enclosed only by a glass window). They also left it open to their bedroom with a glass window and an open doorway. In this way, light flows through to these living areas allowing the couple plenty of natural light for showers, brushing teeth, dressing, etc.

The openness of the home also allows the city to enter their living space. "When you break the edges between outside/inside, it makes the space bigger: at the end our flat is as well the street."

Watch Kirsten's feature-length documentary on tiny homes: "We the Tiny House People: Small Homes, Tiny Flats & Wee Shelters in the Old and New World."