Quote from Wikipedia:

“The Beatles’ rooftop concert was the final public performance of the English rock group the Beatles. On 30 January 1969, the band, with keyboardist Billy Preston, surprised a central London business district with an impromptu concert from the roof of Apple headquarters at 3 Savile Row. In a 42-minute set, the Beatles played nine takes of five songs before the Metropolitan Police Service forced them to stop. Footage from the performance was later used in the 1970 documentary film Let It Be.”

On a personal note, I wasn’t aware of this concert until a few months later when it started to filter across the pond into North America. I was in high school at the time and the Beatles were the coolest band at the time. We used to ask if you were a Beatles fan or Stones. They were a the the top of the heap back then and every other band was secondary. Imagine!