Typically, the narrow corridors in between a city’s buildings are home to garbage cans, discarded fast food bags, and cats. But not all alleys are damp and dark—some are colorful and vibrant, with walls covered in eclectic works of art that captivate the eyes and spirit. Some are massive murals, while others are home to generations of graffiti artists.

Down a tight alleyway leading to the library in Manchester, New Hampshire, visitors can stumble into a cat-lovers haven. Cat Alley is home to dozens of paintings of feline friends designed to honor the alley’s namesake. In the middle of  San Francisco, California, Balmy Alley is home to the most concentrated collection of murals in the city. Its walls have served as a creative canvas since 1972. From a collection of garage doors that creates a drive-through gallery to an ode to famous cartoon and video game characters, here are 15 art alleyways to discover hidden treasures.