Final answer:
Robert E. Lee of the Confederate army surrendered to Ulysses S. Grant at Appomattox Court House in April 1865, which led to the conclusion of the Civil War.
Step-by-step explanation:
In April 1865, Robert E. Lee surrendered to Ulysses S. Grant at the McLean House in Appomattox Court House, Virginia. This marked a significant turning point toward the conclusion of the Civil War as Lee, commanding the Confederate army, gave in to the overwhelming force of Grant's Union army.
Following this surrender, other Confederate forces would also lay down their arms, with General Johnston doing so on April 26, 1865, and General Stand Watie in June 1865, effectively leading to the end of the Confederacy.