This is from Queen's famous "Magic Tour" of Europe, which was their biggest ever tour and also their final tour with the classic lineup of Freddie Mercury, Brian May, Roger Taylor and John Deacon. Their final concert with Mercury as frontman was soon after this one, at Knebworth Park. Because of Mercury's declining health (he was diagnosed with AIDS the following year), they were never able to tour again.
The concert was shot using video cameras, which was then fairly unusual for professional concert footage, which in the 1980s was normally still captured on film cameras. As a result of it being shot on video instead of film, the picture image is slightly softer and bright lights cause noticeable comet trails on the screen.
Filmed on the second night of Queen's two nights at Wembley on 11-12th July 1986, Freddie Mercury's voice was not in as good a shape as it was on the first night, which led to many vocal overdubs being done for the TV/radio simulcast in October 1986 and official releases.
It was rumoured that David Bowie might join the band on stage for "Under Pressure", but it never materialized.