The Thirty-third Street Bridge in Philadelphia carries Thirty-third Street over the former course of Master Street in the Brewerytown section of North Philadelphia, near Fairmount Park

Fairmount Park

Fairmount Park is the municipal park system of Philadelphia, Pennsylvania. It consists of 63 parks, with , all overseen by the Philadelphia Department of Parks and Recreation, successor to the Fairmount Park Commission in 2010.-Fairmount Park proper:...

. The bridge was built in 1901 with an unusual skewed arch

Skew arch

A skew arch is a method of construction that enables an arch bridge to span an obstacle at some angle other than a right angle. This results in the faces of the arch not being perpendicular to its abutments and its plan view being a parallelogram, rather than the rectangle that is the plan view of...

, and listed on the National Register of Historic Places

National Register of Historic Places

The National Register of Historic Places is the United States government's official list of districts, sites, buildings, structures, and objects deemed worthy of preservation...

 in 1988. Ashlar

Ashlar

Ashlar is prepared stone work of any type of stone. Masonry using such stones laid in parallel courses is known as ashlar masonry, whereas masonry using irregularly shaped stones is known as rubble masonry. Ashlar blocks are rectangular cuboid blocks that are masonry sculpted to have square edges...

, or dressed stone, covers the exterior of the arch, but the unusual skewed ribs are made of brick. The underpass is now inside an industrial area and normally closed even to foot traffic.The tracks of the former Pennsylvania Railroad

Pennsylvania Railroad

The Pennsylvania Railroad was an American Class I railroad, founded in 1846. Commonly referred to as the "Pennsy", the PRR was headquartered in Philadelphia, Pennsylvania....

are located just to the north and pass under a large modern bridge on Thirty-third Street.