Philadelphia's main post office hasn't done quite as much traveling as the parcels and letters it distributes, but it hasn't exactly stayed in one place, either. It's had more than 20 locations. Here are some of them:

* Early 1700s: While a postal service exists in Philadelphia, a general post office does not. Instead, appointed postmasters use their own homes as offices.

* 1728: Printer, publisher and bookbinder Andrew Bradford becomes postmaster, and distributes mail from his house on 2nd Street, which also serves as the office for his newspaper, the American Weekly Mercury.

* 1737: Bradford's publishing rival, Benjamin Franklin, is appointed the city's postmaster. The office of Franklin's newspaper, the Pennsylvania Gazette, becomes the new home of the general post office.

* Early to mid-1800s: The U.S. government begins renting space for the general postal service in such buildings as the Merchants' Exchange, which still stands on 3rd Street between Dock and Walnut. The since-demolished Jayne Building, at 238 Chestnut St., also serves as the city's main post office.

* 1863: The first government-owned main post office opens on Chestnut Street, near 5th. Ten years later, construction on a new main post office begins.

* 1884: Philadelphia's main post office finds a new home at 9th and Market streets, in a building that cost a record $4.5 million to build. The post office is still in use today.

* 1935: After three years of construction, the Philadelphia General Post Office at 30th and Market streets opens. The building, which cost more than $6.5 million, becomes the only post office in the world accessible by land, water and air. Its roof features a heliport.

* 2007: After purchasing the Philadelphia General Post Office, the University of Pennsylvania announces plans to redevelop it with Brandywine Realty Trust.

* 2008: Philadelphia's main post office moves across the street to 30th and Chestnut streets, taking over the former Truck Terminal Annex Building, which was built in 1962.