See the best of London's royal highlights on a 4-hour walking tour. Begin with a visit to the infamous Tower of London, where you'll be dazzled by the Crown Jewels and see the Tower Green where traitors and monarchs alike lost their heads. Then, soak up the sights during a 30-minute Thames River cruise before taking in the Changing of the Guard at Buckingham Palace or Horse Guards Parade. End your tour outside the palace, where you'll learn about Queen Elizabeth II and the history of the British Royal Family.