The Edgar Thomson Steel Mill was built by Andrew Carnegie on top of the battlefield. Somewhere underneath the mill are the graves of about 500 British soldiers that died during the battle.  

Battle of the Monongahela

The Battle of the Monongahela, also known as the Battle of the Wilderness, took place on 9 July 1755, at the beginning of the French and Indian War, at Braddock's Field in what is now Braddock, Pennsylvania, 10 miles (16 km) east of Pittsburgh. A British force under General Edward Braddock, moving to take Fort Duquesne, was defeated by a force of French and Canadian troops, with its Native American allies.

• http://en.wikipedia.org/wiki/Battle of the Monongahela