Urban apartments are getting smaller and smaller, but one 'home' in Warsaw, Poland, may push the limits to what is humanly accessible.

The Keret House was conceived by Polish architect Jakub Szczesny when, about six years ago, he spotted a narrow yet 'appealing cushion of air,' between two buildings. The space was one of those ubiquitous but discarded gaps in cities that remain unused except for trash buildup.

TwentyTwoWords.com reported that Szczesny cleared some city hurdles, got permission to build the property and found a German construction company to put his blueprint together.

Though the structure, which was completed in 2012, could be used by traveling writers, country law reportedly describes it as an art installation. An Israeli writer has stayed inside the house that is a fully-functional home that measures, at its widest, 48 inches. 

The two-story aluminum and plastic house fills a narrow space between a pre-war house and a modern apartment block in downtown Warsaw. The Foundation of Polish Modern Art and Warsaw Town Hall helped fund the project.

Metal and aluminum pipes hold the structure nearly 10 feet above the ground, and visitors will climb a metal staircase and squeeze through a hole to enter the building.

The ground floor contains a toilet and shower, a kitchen with a sink and cupboards, a table for two, and a bean bag sofa. Another metal ladder goes to the second floor, which has a nearly double-size bed, a table and a chair.

Szczesny said that the building achieves two goals: filing an empty city space and linking Warsaw's World War II tragedy, when more than half the city was destroyed, with modern buildings that went up afterward.

He said he only visits Warsaw twice a year, so other tenants will be able to try out the tight quarters of the non-profit building for free, too.

The Associated Press contributed to this report