During which American Civil War campaign did Union troops dig a tunnel beneath Confederate troops to detonate explosives underneath them?

The answer is Siege of Petersburg because during this campaign, Union troops, under the command of General Ulysses S. Grant, launched a bold operation to undermine Confederate defenses by building a tunnel underneath their fortifications. The tunnel, meticulously constructed by Union soldiers, was filled with explosives and then detonated on July 30, 1864, resulting in a massive breach in the Confederate lines. This tactic aimed to break the stalemate and prepare the way for a successful Union assault on Petersburg, ultimately leading to the Confederacy's defeat in this critical campaign of the American Civil War.