The lives of 30,000 Confederate soldiers were lost during the Siege of Petersburg , one of the most devastating events of the Civil War. Blandford Church, built in 1735, now honors their memory. Here, at their graves, the first Memorial Day was observed in 1866. Fifteen Tiffany stained-glass windows, designed in their honor, adorn the building. Donated by southern states after the war, this is one of only seven complete sets of Tiffany windows in existence.