what is it famous for?
Traditional bespoke tailoring for men, accommodating the headquarters of the Royal Geographical Society, and Beatles' roof top live performance
Savile Row
Known principally for its traditional bespoke tailoring for men, the street has had a varied history that has included accommodating the headquarters of the Royal Geographical Society at 1 Savile Row, where significant British explorations to Africa and the South Pole were planned; and more recently, the Apple office of the Beatles at 3 Savile Row, where the band's final live performance was held on the roof of the building.

who held a live performance on the roof top of three savil road of mayfair in 1969 The Beatles where is this place located? Mayfair, central London
wiki:17810605
Savile Row [SEP] Introduction
Founded in 1849 by Henry Huntsman, H. Huntsman & Sons moved to No. 11 Savile Row with the ending of the war in 1919. During the First World War, Huntsman's was a tailor to the military, producing dress uniforms for British officers throughout the conflict. In 1969, Nutters of Savile Row modernised the style and approach of traditional Savile Row tailoring; a modernisation that continued in the 1990s with the "New Bespoke Movement", involving the designers Richard James, Ozwald Boateng, and Timothy Everest. The term "bespoke" as applied to fine tailoring is understood to have originated in Savile Row, and came to mean a suit cut and made by hand.