To 22 ports; the busiest crossings are to Canary Wharf (4 minutes, 38 times a day), Battersea Power Station (55 minutes, 38 times a day), Greenwich (8 minutes, 37 times a day), North Greenwich (18 minutes, 37 times a day), Tower of London (16 minutes, 36 times a day), London Bridge (20 minutes, 36 times a day), Bankside (24 minutes, 36 times a day) and Embankment (36 minutes, 36 times a day).