The White House is actually one of Washington, D.C.'s oldest buildings and a good place to begin your exploration of the city. To participate in an official tour of the White House you need to make your reservations at least 6 months in advance. The world's largest obelisk was erected in honor of the first U.S. president George Washington, and across the mall from it sits the Lincoln Memorial, named after the 16th president of the country. Both of these, along with the 200 year old congress on Capitol Hill building have become symbols of the city and the country. The National Gallery has an unbelievable collection of famous works as well. If you want to get away from the center of politics, along the Potomac River in Georgetown there's some lovely shopping to be done on your way across the river to the old town of Alexandria.