Allegheny Arsenal

Bruce Smith / AP

Authorities in western Pennsylvania say a construction crew found a cache of buried cannonballs at the site of an old civil war arsenal in Pittsburgh.

Public safety officials say the crew found about 20 cannonballs Monday at the site in the Lawrenceville neighborhood.

The police bomb squad responded to the scene but decided to allow the construction company's subcontractor to remove the cannonballs.

University of Pittsburgh Libraries / flickr

Paint a picture of Pittsburgh in the summer of 1863 and it becomes evident why many once thought the city could be a target for an attack from the Confederate Army.

The Steel City housed scores of factories and foundries as well as the Allegheny Arsenal in Lawrenceville. All of these industries were ideal for producing war materials.  A take over of the city could provide the South with equipment and resources that other Pennsylvania cities, such as Harrisburg, could not supply. This industry coupled with its placement as a transportation hub at the three rivers allowed the city to stand out to many prominent figures of the period, including President Abraham Lincoln.