Blue walls of Chefchaouen, Morocco (© AnetteAndersen/Getty Images)

Chefchaouen, known as the 'Blue Pearl' of the Rif Mountains, is one of the most atmospheric cities in Morocco. Its name comes from a blend of Arabic and Berber—Chef, derived from the Arabic word meaning 'to look,' and Echaouen, a Berber term for 'horns'—together meaning 'look at the horns,' a reference to the two mountain peaks that rise above the town.