 In 2003, the creator of the "Case Closed" series, Gosho Aoyama, had stated he would draw a story arc taking place in London.To this end, he traveled to London and visited the sites that would appear in the story arc; for sites he had not visited, he used Google Maps.During his trip, Aoyama took special note of a phone booth near Big Ben and a drain pipe, engraved with the words "Valley of Fear", on the Westminster Bridge; these two aspects were used in the story.