Tours, conducted on open-top coaches, are covered for 24 hr. with a ticket, so you can go around five times if your feet hurt. You can catch the bus (three interconnecting circuits that supply solid coverage of the main sights) at any of the 80-odd stops on the routes, but most people begin at Piccadilly Circus, Trafalgar Square, Embankment Station, near Victoria Station, or outside Madame Tussauds. Live narrators appear, without much vigor or inspiration, on the Yellow Line, which covers the broadest swath of town, while other lines are likely to have digital spiels, sometimes too quiet to hear. Two of its routes come with audio/booklet packs for kids, but you have to pick them up at its office.