Bubble Gum Alley is located in San Luis Obispo on Higuera Street. The alley is the city’s most popular unofficial landmark, It is a 15-foot (4.6 m) high and 70-foot (21 m) long alley lined with chewed gum left by passers-by. The gum started appearing on the walls in 1960. People complained but the gum kept on coming. The wall is not a random collection of gooey gums, some people in San Luis Obispo...