La Estrecha House

This extremely skinny building holds the record for the narrowest façade in Europe. Measuring 107 centimeters (42 inches) wide, La Estrecha (Narrow One) could be considered the narrowest house in Europe and maybe in the world.

Certainly, there is competition for the title. Poland's Keret House was built in 2012 and measures just 72 centimeters (28 inches) at its narrowest point, but it reaches a width of 122 centimeters (48 inches) in the façade. And in Amsterdam, the façade of Singel 7 is just 105 centimeters (41 inches) wide—but behind that extremely narrow front sits a standard-width home.  

Located in Valencia's Plaza Lope de Vega, this house was originally built as a family home. Each of its five floors was made up of a single room: the ground floor served as a family-run jewelry shop, and the floors above held a small dining area and bedrooms, all joined by a spiral staircase. In the 1980s, an indoor refurbishment led to the removal of an inner wall, so technically the property is part of the restaurant in the adjacent building. But the five-story building has preserved its own front door so from the outside, it still looks like a separate structure.