If you go no where else in London, you must go to Westminster. The London zoo is located here and is the most famous in the world. It has been serving the children of London since 1847. The zoo is home to over 650 species and has an animal conservation center. Tours are available for both leisure and academic visits. Leicester Square is much like Hollywood's walk of fame, except for stars in the sidewalk with hand prints, there are plaques with handprints of some of the most contributing members of England's movie and entertainment industry. It is close to the river Thames, which offers sights for the traveler that are typically seen only in postcards.
Buckingham Palace, official residence of Her Majesty, The Queen of England, is located in Westminster and tours of part of the palace are available. Not the entire Palace, of course, the Royal Family does live there, after all. The state rooms are open to the public in August and September yearly. The Queen's Gallery is open all year round, and The Royal Mews is open from late March to October. Come to see the changing of the guards as it is one of the premier, if not the premier attraction in London.