Central Warsaw is truly crammed for space, and many downtown developers are turning horizontal space into vertical space by building tall skyscrapers. But in no other setting in the world is a building’s height to width ratio as insanely preposterous as that of Warsaw’s Keret House. Welcome to the skinniest house in the world.

Designed by Polish architect Jakub Szczęsny, the Keret House in Warsaw is wedged inside a four-foot crevice, nicknamed a “cushion of air,” between two buildings. The Keret House stretches over 30 feet tall but is simultaneously only 28 inches wide at its narrowest point—thinner than a stovetop—and just four feet wide at its widest.

With just 46 square feet of floor space and a world record for narrowness under its name, the Keret House manages to fit a bedroom, a bathroom, a kitchen, and a two-beverage refrigerator in the span of three floors. The first floor features nothing but a staircase to the second. However, when the staircase is retracted it makes for a pleasant (yet claustrophobic) living room. To get from the second floor to the third, you must climb a white ladder.

Since the Keret House is so minuscule, it has no room for traditional electrical and sewage appliances. Szczęsny’s makeshift solution to the electrical dilemma involved obtaining electricity from the two buildings it’s sandwiched in between. To dispose of sewage, the Keret House avoids city standards and instead uses an innovative customized design.

Built in 2012, Szczęsny’s narrow masterpiece is legally classified as an “art installation” because it doesn’t meet Polish housing codes, but, in practice, it serves as a residence nonetheless. Constructed as a memorial to his family killed in the Holocaust, the Keret House is named after Etgar Keret, the Israeli filmmaker and author who was spontaneously asked by Szczęsny to be the house’s first tenant. After Keret agreed to the deal and lived there for a number of weeks, the Keret House became open to traveling writers for the night’s stay. As of today, the Keret House is open to all visitors to Warsaw, so long as it’s not undergoing maintenance.