Boats and Bikes

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The Bert's Barges houseboat hotel on Regent's Canal in Hackney couldn't be any cooler if it tried and is a perfect base from which to explore London. Take the free bikes offered and ride 20 minutes to the Tower of London Pier, right next to Her Majesty's fortress by the Thames.
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Use your Oyster card (complementary provided by the barge hotel, make sure it's loaded in advance) to get a discount on the Thames Clipper's service to Greenwich pier. Up to 10 bikes are allowed on each service, free of charge, so bring yours onboard with. The boat's half-hour trip will provide some incredible views of the city from an interesting angle.
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After disembarking in Greenwich, explore this gem of a park complete with another boat - Cutty Sark - this one out of the water works and a museum. Ride uphill to the Prime Meridian (Greenwich) line, and put one foot in the West and one foot on the East Hemispheres. The Royal Observatory is another popular attraction nearby. The views over the city are unparalleled and the Pavilion Tea House will come in handy any time of the day for a delicious cuppa and snack. After doing your bit of touristy sight-seeing for the day, follow the signs on the bike paths to The O2 on North Greenwich peninsula.
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You are not here for a concert or to see inside this extensive entertainment complex, but to climb to the top of the 365 meters of this monster dome. Full climbing kit is provided as well as the guides who will show the way up and down. The unique 360 views over the Thames and the city are worth every cent of this exciting adventure. 
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Back on the ground, cycle 10 minutes back to Greenwich Pier to the Paul Rhodes Bakery on King William Walk on the edge of the park behind the Cutty Sark, for a soup-sandwich-pastry kind of meal.
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From here you can board the Thames Clipper service to the Tower of London pier back into town. Or if there is still some energy left to burn, ride back to Bert's Barge. Crossing the river using the foot tunnel under, pedal through the Isle of Dogs, along the Thames in Canary Wharf with its huge sky-scrappers, towards Mile End, crossing through it into Millennium Park towards Victoria Park and there Regent's Canal will welcome you back home. Be warned that you will hit some busy roads and junctions if cycling back and the trip last about 30 minutes at a steady pace.