Hi, I'm Ben Arrona, here for About.com. I'm a historian with a Master's degree in American History and today we will be discussing the Oklahoma City bombing.On the morning of April 19th, 1995, just after 9:00 a.m., a massive homemade bomb went off in the front of the Alfred P. Murrah Federal Building in Oklahoma City, destroying the nine-story structure and taking the lives of 168 people. It was the worst terrorist attack on U.S. soil at the time. Here's a closer look at what happened.While the events of that fateful day seemed to come out of nowhere, they were the culmination of a long building plan by the culprit, Timothy McVeigh. McVeigh was a 24-year-old ex-military man when the ATF raided the Branch Davidian cult compound in Waco, Texas on April 19th, 1993. That raid, which McVeigh viewed as an illegal use of government power, resulted in the death of 75 people. Fueled by this notion, and aligning himself with the views of the radical, right-wing, Militant Patriot Movement, McVeigh set out to exact revenge on those whom he saw as the guilty parties in the Waco tragedy.He soon recruited fellow ex-Army soldier and Militant Patriot, Terry Nichols, to his cause, and the two began putting together the plot that would eventually become known as the Oklahoma City bombing. In September of 1994, McVeigh acquired massive amounts of ammonium nitrate-based fertilizer. This highly explosive matter would comprise the main element of his bomb. He and Nichols then stole the remaining ancillary pieces required to construct the bomb from a Kansas quarry. On April 17th , 1995, McVeigh and Nichols loaded a rented moving truck with 5,000 pounds of ammonium nitrate fertilizer.On April 19th, 1995, exactly two years to the day of the Waco tragedy, McVeigh parked the now-armed moving truck in front of the Murrah Federal Building in Oklahoma City. The building housed a number of offices used by the ATF, one of the agencies McVeigh held responsible for Waco. He lit the fuse and left the scene. At 9:02 a.m., the ammonium nitrate bomb exploded, destroying all nine stories of the Murrah Building. It would take rescuers weeks to recover all of the victims.In all, 168 were killed -- 19 of them were children. McVeigh and Nichols were arrested shortly thereafter and convicted in Federal court for the crimes. Timothy McVeigh was sentenced to death and Terry Nichols was given life in prison. A third accomplice, Michael Fortier, was given 12 years in prison for his role. In 2000, the Oklahoma City bombing Memorial was completed on the location of the bombing. It stands as a reminder of the lives lost on that infamous day.Thanks for watching. To learn more, visit us on the web at About.com.