This video is filmed inside the remains of the largest nazi concentration camp (where the Germans killed thousands and thousands of jews, political prisoners, homo-sexuals, among others, during the second world war 1939-1945). The Auschwitz concentration camp is located in Poland, Balka's origin), and the entrance gate reads the very famous words 'ARBEIT MACHT FREI', which roughly translated means 'work shall set you free'. This is of course, due to history, one huge terrible lie.
In the video one sees a B (in reverse) and this B is from the ARBEIT MACHT FREI, so this means that the viewer is actually located inside the gate/boundary of the camp. Meanwhile, snow is silently falling, and it's strangely beautiful despite the terrible context. Also one hears children's laughter, which makes everything even more absurd.