The United States National Archives last week released an animated graphic (below) showing the daily distribution of US airstrikes over Cambodia, Vietnam and Laos between October 2, 1965 and August 15, 1973.

The graphic shows a detailed analysis of bombing campaigns using data pulled from the US Air Force, Marines and Navy.

The animation was created for an ongoing exhibition that runs through January 2019 at the US National Archives Museum in Washington, DC titled Remembering Vietnam: Twelve Critical Episodes in the Vietnam War.

The exhibition is the first ever by the National Archives on the Vietnam War and features a trove of archival records spanning six presidential administrations as well as newly declassified information, according to a press release.

Clearly visible in the video – in which daily bombing strikes are marked as red dots – is the start of the first concerted US bombing campaign in Cambodia: the secret Operation Menu, which started under US President Richard Nixon and lasted from March 18, 1969 through May 28, 1970.

Before this, bombing operations were conducted in Cambodia beginning on October 4, 1965, according to the archives.

Bombing runs continued until August 15, 1973, to the end of Operation Freedom Deal. According to Yuki Tanaka and Marilyn B Young’s, Bombing Civilians: A Twentieth-Century History, more than 2.7 million tonnes of explosives are estimated to have been dropped on Cambodia by the US.