Morocco is famed for its colorful markets, towns and cities, but the northwestern city of Chefchaouen has a singular take on its color scheme. In fact, it’s rare to find a building in the town that’s not painted completely blue or at least decorated in shades of blue.

Chefchaouen was founded in 1471 as a safehaven for Jewish and Muslim refugees from the Christian Reconquista of Spain and Portugal. These refugees brought a distinctly Andalusian flair for domestic architecture and the practice of adding balconies, patios and tiled roofs to houses. The Jewish immigrants also brought the city’s trademark blue-wash decoration.

Originally, the blue pigments used in covering the town’s buildings was derived from the shells of sea snails called tekelet. And the practice of blue-washing walls was based on the Biblical injunction “speak to the Children of Israel and bid them that they make fringes on the corners of their garments…and that they put upon the fringe a thread of blue (tekhelet)” , Numbers 15:38-39. The Iberian jewish refugees just got carried away.

For centuries, Chefchaouen was closed to foreigners, especially Christians. A few daring travelers, including French explorer Charles Foucauld and English journalist/travel writer Walter Harris visited the city disguised as Jews. Today the town is a popular getaway for Spanish tourists, especially young people who come to purchse cannabis products in Chefchaouen’s medina.