London CNN  —  A pair of gently curved bridges, a bronze oak tree and a lily pad-inspired walkway are among the standout features of five shortlisted designs for Queen Elizabeth II’s official memorial site in central London. The national memorial will be built in St. James’s Park, near Buckingham Palace in the heart of the British capital. The finalists, unveiled Wednesday, include some of the UK’s most prominent architecture firms, including Foster + Partners, which designed London’s City Hall