Buckingham Palace
Westminster - London, UK
This is the second royal palace that I've had the opportunity to visit in my life.  I saw my first when I was eight years old - 
Iolani Palace in 
Honolulu.  It only took 26 years for me to see another.  Unfortunately, 
Buckingham Palace wasn't open for tours (that's usually limited to the summer and a few select dates in the Fall and Winter), but it was still very cool to see the home of 
Queen Elizabeth.