This is Buckingham Palace, the official London residence of the British monarch. It did not become the official royal palace of the British monarch until the accession of Queen Victoria in 1837. Queen Elizabeth II now resides here.
Typically, the public isn’t allowed to tour Buckingham Palace, but in 2009 the Palace began to hold tours during the summer/fall (when the Queen is at her summer residence in Scotland) in exchange for a sum of money from the British government that would pay for repairs to the palace. Tickets to the palace are £17.50, a rather pricey sum (especially for a student – my mom made me go ;)), but well worth it if you have an interest in the royal family and have the funds to splurge after booking a stay at one of the luxury hotels in the UK.
The Buckingham Palace tour takes you through nineteen of the Palace’s State Rooms, which are used by the Royal Family to receive and entertain guests on official occasions. On the tour you will see a ton of chintzy knick knacks as well as museum-worthy paintings and sculptures by some of the world’s greatest artists (which makes one wonder why the UK government is providing the Royals with funds, but I digress…). At the end of the tour, you can walk inside the walled-off Palace garden, which quickly makes you forget that you are in the middle of a huge city. And, of course, if you felt that you haven’t given the Royal Family enough of your money, at the conclusion of the tour you can go into the Palace gift shop and buy a variety of souvenirs (Queen Elizabeth II shot glass, anyone?)