The Amsterdam Royal Palace
Although you can see Buckingham Palace on Google Maps, you wont have as much luck in the Netherlands. Several buildings owned by the Dutch royal family have been censored. These include the Koninklijk Paleis (the royal residence), the royal stables, and the Huis ten Bosch.
Rather than blocking out the entire are, Google has effaced some details. Parts of a roof or gate will appear fuzzier than the surrounding area. Nobody knows why these specific areas have been pixelated.