On 19 April 1995, America suffered its first ever domestic terrorist attack in Oklahoma City, when a bomb went off at a federal government building.
150 people were killed - including 19 children at a newly opened daycare centre on the first floor.
At first Muslim extremists were blamed, but it eventually became clear that the bombers came from closer to home. Two Americans were arrested - Timothy McVeigh and Terry Nichols - both with links to white supremacist groups. The former was sentenced to death, and the latter to life imprisonment.
Watch original British Pathe footage from the bombing above.