#44 in the Nancy Drew mystery book series visited Machu Picchu, too!

From a reader review on Amazon.com:

"In "The Clue in the Crossword Cipher", Nancy meets a young girl from Peru, about her same age, named Carla Ponce. Carla asks Nancy to solve her "monkey mystery" (which I will not give away) and along with Nancy's best friends, Bess Marvin and George Fayne, the four of them set out to solve the mystery. They explore South America and go to places like the Argentine, Cuzco, Peru, and lastly, the Nascan Lines, a desert in South America. I recommend you read this amazing book and all the others in the Nancy Drew series, too.