This photo made on Tuesday, Sept. 11, 2012, shows Arsenal Park in the Lawrenceville neighborhood of Pittsburgh. The area was part of the site of the Allegheny Arsenal that was established in 1814 by the U.S. Army Ordnance Department. On the afternoon of Sept. 17, 1862, a series of explosions ripped through buildings where cartridges for union soldiers were being assembled, killing 78 people, most of them teenage girls. In recognition of the 150th anniversary of what is thought to be the largest loss of civilian life on a single day in the Civil War, local historians plan a day of memorial services for Sunday, Sept. 16, 2012. (AP Photo/Keith Srakocic)