GETTYSBURG, Pa. — The Union and Confederacy are meeting again at Gettysburg as re-enactors fired the opening volley from their muskets to begin the commemoration of the 150th anniversary of the pivotal Civil War battle.

About 200,000 people are expected to visit the small, south-central Pennsylvania town for a 10-day period starting Friday. It's a momentous week for Civil War buffs — especially the thousands of men and women portraying soldiers, doctors and other personnel from the period.

The first of two re-enactments began Friday morning. The National Park Service's official ceremonies begin Sunday. The actual anniversary is July 1-3, 1863.

The events are years in the making after being jointly planned by the Park Service and a host of community organizers and volunteers. A visitors bureau spokeswoman says things are off to a good start so far.