Did you know . . .

A standard blue U.S. Postal Service mailbox will hold approximately 4,000 letters.

Introduced in 1782, Mercury, the messenger of the Roman gods, was the first symbol of the U.S. Post Office. In 1837, Mercury was replaced by a postal rider on horseback, who was replaced in 1970 by the American Eagle. The eagle was updated in 1993.

In 1865, when the Secret Service was established to combat counterfeiting, fully one-third of all the currency in circulation in the U.S. was thought to be counterfeit.