From the White House to Downing Street to the Élysées Palace, what is a presidential residence in December without a sparkling Christmas tree?
The Obamas sang with Justin Bieber and Jennifer Hudson in the National Building Museum. In years past, international leaders have made sure not to miss a single opportunity to show off their royally decorated holiday centerpieces. In 2010, France's Nicolas Sarkozy happily posed with Lebanese president Michel Suleiman in Paris, and Germany's Angela Merkel proudly posed next to one of the chancellery's three Christmas trees.
Take a look at world leaders in their Christmas finery in the slideshow below. Who has the best tree?