13 Little Blue Envelopes (2005) by Maureen Johnson is a summer teen adventure about backpacking through Europe. Ginny is a shy teenager guided through a zigzagged tour of Europe by 13 letters her deceased Aunt Peg had left for her. Ginny is awkward and quiet, the opposite of her late aunt, a vivacious, eccentric artist. Aunt Peg wished for Ginny to come out of her shell, so she sent her on a scavenger hunt through the UK, Rome, Paris, and Amsterdam, among other countries in Western Europe before she died. Along the way, Ginny makes new friends and learns more about her aunt’s mysterious past in this lighthearted travel story.