London’s iconic buses still ply the city's streets, providing several million rides each day. Two “Heritage Routes” feature old-style “Routemaster” double decker buses and an on-board conductor who collects fares from passengers. The modern version of the double decker is just as good if you are looking to see some of London's best sights from street level.
With more than 700 routes around the city, it is pretty easy to find something that runs near the places that you want to see. Because of London's traffic, the Tube is a much faster option for getting around the city, but buses are infinitely better when it comes to the view. Prepaid Oyster Cards (for use on all London public transit) and multi-ride bus passes make it easy to hop on and hop off public transit at will. A popular sightseeing bus route is the No. 74 route, which passes museums, the famous Harrods Department Store and Baker Street. Meanwhile, the No. 9 bus runs through Trafalgar Square, and the No. 24 offers glimpses of Leicester Square, Big Ben, and Westminster Abbey.