The Confederates burned Richmond as President Davis and his cabinet fled to make sure the Union Army could not use Confederate resources.
During the American Civil War, Richmond became the capital of the Confederate States of America.
On April 2, 1865, more than 25% of the buildings in the city were destroyed by fire after the withdrawal of the Confederate soldiers, who burned all the Confederate resources to make them unusable for the Union.
On April 3, 1865, Ulysses S. Grant and the Union Army captured Richmond, and the state capital was then transferred to Lynchburg. The Army of North Virginia, commanded by Robert Lee retired and surrendered six days later before Grant in the Appomattox Court House, becoming the symbolic end of the war.
The industrial revolution increased the power and wealth of "factory owners" mostly, but this is a misleading question, since the revolution increased the wealth of practically everyone except the aristocracy.
The Battle of Gettysburg, Pennsylvania (July 1–July 3, 1863), was the largest battle of the American Civil War as well as the largest battle ever fought in North America, involving around 85,000 men in the Union’s Army of the Potomac under Major General George Gordon Meade and approximately 75,000 in the Confederacy’s Army of Northern Virginia, commanded by General Robert Edward Lee. Casualties at Gettysburg totaled 23,049 for the Union (3,155 dead, 14,529 wounded, 5,365 missing). Confederate casualties were 28,063 (3,903 dead, 18,735 injured, and 5,425 missing), more than a third of Lee’s army.
I am pretty sure it's Great Britain.