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9 of the world's thinnest buildings

Narrow house in Old San Juan, Puerto Rico

Photo: bjornman/flickr

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La Casa Estrecha, Old San Juan, Puerto Rico

La Casca Estrecha in Old San Juan, Puerto Rico, is 5 feet wide on the inside and has two stories that stretch back 36 feet. It was once a home but is undergoing renovations to be transformed into an art gallery.