A messenger bag (also called a courier bag) is a type of sack, usually made out of some kind of cloth (natural or synthetic), that is worn over one shoulder with a strap that winds around the chest resting the bag on the lower back. Messenger bags are often used by bicycle messengers, though they have increasingly become an urban fashion icon. This type of bag has been used in the transportation of mail and goods by numerous types of messengers, including Pony Express riders, postal workers, messengers on foot (especially in ancient times), and bicycle couriers...