The Liberation
Following several days of cease-fire negotiations between the Wehrmacht and the British Army, British troops took over the Bergen-Belsen concentration camp without a fight on 15 April 1945. Shortly beforehand, the SS had destroyed the camp's administrative files to erase all written evidence of their crimes. The British soldiers were utterly unprepared for the inferno they encountered when they entered the camp. For thousands of the at least 53,000 prisoners, liberation came too late. Although the British Army and various relief organisations quickly arranged for medical aid, another 14,000 liberated prisoners had died of the effects of their imprisonment by June 1945 alone.
When the British soldiers took over the camp, they disarmed the remaining SS personnel and placed them under arrest. In the following days, both male and female SS members had to dig mass graves in the grounds of the former camp and bury tens of thousands of bodies.
The British troops were accompanied by military photographers and cameramen whose job it was to document the conditions in Bergen-Belsen and the emergency aid measures initiated there. The hundreds of photos, film reels and notes they took from the day of liberation through June 1945 give some indication of the extent of the crimes committed in Bergen-Belsen. Many of these photographs were published around the world, and they have had a lasting impact on the memory of the Nazi concentration camps worldwide.

(The text was taken from the page "A place of Remembrance" of the "Stiftung niedersächsische Gedenkstätten")

A sign was installed from the British Army at the former entrance to the camp on 29 May 1945:

The first thing to see after entering the memorial site are the mass graves that are spread across the area. After the camp was liberated, the British Army found thousands of dead prisoners. To avoid epidemics, the dead had to be buried as quickly as possible. Thousands of the dead found their final resting place in these graves. Within the boundary of the memorial site, Bergen-Belsen has 14 mass graves containing at least 23,200 former prisoners.