LondonWhether it's Buckingham Palace, the Houses of Parliament or Trafalgar Square, London's sights are instantly recognizable. Blessed with a historical grandeur, from the Tower of London to the Inns of Court, the city's past provides ample opportunity for aimless, misty-eyed strolling. Its museums are global big hitters, the brutalist Tate Modern and the National Portrait Gallery showcasing the finest art around. And its royal parks are the ideal spot for spending a sunny afternoon, whether it's boating in Regents Park or taking a swim in Hyde Park's Serpentine. Adventurous visitors can take advantage of London's superb Tube and rail system to explore distant neighborhoods, from leafy Hampstead to hip Hackney.