LONDON (REUTERS).- A mile-long floating walkway on London’s River Thames is being planned in the heart of the capital, allowing views of the city’s hidden alleys, wharves and landmarks dating back to medieval times. The pontoon, known as the “London River Park,” will connect Blackfriars Bridge, on the western edge of the ancient city, and the Tower of London in the east. Suspended a few feet above the water on the north bank, the walk will be interspersed with five glass-encased pavilions housing a museum, a cinema, a concert hall and an eco-park amongst other attractions. Swimming pools are central to drawings of one futuristic-looking enclosure. The “promenade,” to be built in time for the Olympic Games and the Queen’s Diamond Jubilee in 2012 — if funding is found — won the Mayor of London’s award for planning excellence last week. The mayor, Boris