architecture blocks boats buildings city cityscape England english Great Britain landmarks London river shard skyscraper thames tower urban view water monument branches climb hidden hide hideaway hunt hunter hunting hut limb rundle rundles rung rungs spoke step steps to the top tree house upwards battleship Tower of London transport cathedral church St Paul's bridge Canary Wharf Tower Bridge line London Eye railway train wheel boat Gherkin Walkie Talkie London Bridge rush hour tower blocks track