The cannons boomed and the guns flared as the mists of times parted, and north and south squared off again on a Virginia field in a living reminder of the first major battle of the Civil War. \"We know the war is over,\" said Ron Miller, proudly attired in the uniform of the southern Confederacy, which went on to win this battle 150 years ago, though not ultimately the war. But he said \"it\'s important that our country remembers its heritage and its history. I do this to teach our history to our children.\" This weekend, under baking hot temperatures, thousands of spectators were gathering to watch a re-enactment of the Battle of First Manassas/Bull Run, fought on July 21, 1861 at Manassas, in the southern state of Virginia. Miller, whose great-grandfather and great-great grandfather fought in the four-year Civil War, is one of hundreds of history fans who at weekends don the uniforms of their forefathers and reenact battles from the war that forged modern-day America. \"Look how they load the cannon,\" Miller, 60, told children watching him intently as more than 8,700 reenactors as well as some 375 cavalry horses from the US, Canada and Europe were Saturday and Sunday recreating history here. The re-enactment of the battle is just one of hundreds of events being held around the United States to mark the 150th anniversary of the start of the 1861-1865 war. \"I\'ve always been fond of history,\" Miller told AFP, saying he was inspired by the tales handed down by his relatives. His great grandfather had even enlisted at 14 and fought in every major engagement. Across the vast site outside Manassas, white tents were erected to serve as bivouacs and give historical insights into life in this corner of the South, 150 years ago. A man dressed in the style of a French Zouave soldier was taking a nap, as lone violinists played softly nearby. Despite the baking sun, Kevin Zepp, 60, stood tall in his simple gray wool trousers marked with the colors of his Alabama regiment. \"If you were a farmer or a worker in a factory, you had these trousers. It\'s like the modern jeans, you put the military stripes on it,\" he explained. Sheltering under a tree, Karen Quanbeck, 52, explained that she was playing the role of Catherine Barbara Broune, a peasant woman who had worked with her brother, a priest, to transport the wounded and find medicines. And while this weekend\'s events hold a special historical significance, there are hundreds of volunteers who dress up in costumes throughout the year to bring the Civil War back to life across the country. \"We meet once a month,\" said retired teacher Nancy Anwyll, from Springfield, Virginia. \"I\'ve had an ancestor in the Civil War on both sides. I\'m trying to learn more what they had to endure, I have to learn what they went through.\" War broke out in April 1861 soon after 11 southern states formed the Confederate States of America. While the exact causes of the war are still hotly debated, there is no doubt that an over-riding issue was slavery. The agricultural South relied heavily on slaves to work their rich cotton plantations and feared the new US president, Abraham Lincoln, would eventually set them free. While Lincoln declared an end to slavery in 1863, race relations remain one of the nation\'s most divisive issues. \"A lot of differences we had during the civil war do exist today -- the state rights, the race relations -- there\'s a lot of things we can still work out today,\" said Dennis Rabida, 46, from New Jersey. Retired soldier Dan Byers said he had come to \"honor his ancestors,\" recalling that the northerners had \"invaded our country,\" the South. The clashes in Manassas were ferocious, pitting a northern Union army of some 30,000 against a slightly smaller Confederate force. In the end, the Confederates won the battle, although they were to go on to lose the war. About 5,000 troops on both sides died on the Manassas battlefield that day, but by the end of the war, the toll was 600,000 lives lost.