Washington, D.C.

The only thing more impressive than the sheer diversity of attractions in Washington, D.C., is the fact that most of them are free. In a single day (and for less than a penny), you can see a baby panda at the National Zoo; ogle the Hope Diamond, Dorothy's ruby slippers, and the original star-spangled banner; and watch history being made during a session of Congress. Indeed, you could spend an entire week just exploring the 137 million objects stored in the Smithsonian's 17 museums, including the National Museum of the American Indian (which has the best cafeteria on the Mall), the Air and Space Museum with its futuristic flight simulators, the Natural History Museum and its towering collection of dinosaur fossils, and the newly reopened National Museum of American History. Few visitors have the time (or stamina) to make it through all the museums on one trip—focus on three or four, and perhaps pop in to a few others to see a favorite painting or artifact. (Another benefit to the lack of admission fees at the Smithsonian: Entering is a breeze.) Other free and unmissable sights include the monuments lining the National Mall, particularly Maya Lin's moving Vietnam War Memorial. Visiting non-Smithsonian museums requires a bit more planning: Reserve ahead of time for popular spots like the interactive Spy Museum or the poignant and sobering Holocaust Museum. Make time to get out of the city to see George Washington's Mount Vernon estate in Virginia. Also outside the city is the sobering Arlington National Cemetery, where you can pay your respects at the Eternal Flame.

The real heart of D.C. beats on Capitol Hill and at the White House. Even the most jaded of tourists will have a hard time quelling their patriotism when walking under the soaring dome of the Capitol rotunda or gazing upon the expansive lawn of 1600 Pennsylvania Avenue. And there's never been a better time to visit: The new administration has brought with it a more accessible vibe, and the 2008 opening of the Capitol Visitors Center makes touring Congress an infinitely more pleasurable experience, with extensive on-site facilities, interactive exhibits, and a streamlined online reservations system. Visiting the White House, on the other hand, remains nearly as difficult as winning the presidency: You'll have to write to your Congressional representative as much as six months in advance to get inside, and even then, tours are only available to groups of ten or more. Another way to take the nation's political pulse is by eavesdropping on the lobbyists sipping expense-account reds at the Oval Room or hanging with the young Obama staffers unwinding over Belgian beers at Marvin.