The United States Postal Service is the body that controls all mail from the United States and operates as an independent government body. The USPS is the one who established the zip codes system, an efficient system that differentiates the zones from five digits, and has the possibility to add more numbers to this code to make a service even more efficient. Perhaps the zip number most famous in the world is the Beverly Hills zip code, 90210, thanks to the TV series that was called so and was a worldwide success.