More than a city, but not quite a state, Washington, DC, was created by Congress in 1790 as a place to meet and transact the affairs of government.

Today, visitors to our nation's capital can keep infinitely busy with artsy, scientific, political and historic happenings. Watch a million dollars get printed; see a baby panda; learn about the Concorde aircraft; and relive the history behind the Hope Diamond.

US Supreme Court

Gorgeous marble and architecture notwithstanding, the real reason to visit the imposing neoclassical building isn't what you see so much as what you hear:

"Oyez! Oyez! Oyez!" cries the Marshal of the Court, introducing the opening of this highest court of law in the land and inviting citizens to give a listen as nine black-robed justices defend the Constitution.

The oral arguments are 30-minute presentations by each side's attorneys, followed by a 30-minute question-and-answer session with the justices. These are open to the public, but seating is on a first-come, first-seated basis. Before a session begins, 2 lines form on the plaza in front of the building: one for those who wish to attend an entire argument; the other, a 3-minute line, for those wanting to observe only briefly.

The argument calendars are posted on the Supreme Court's web site under the "Oral Arguments" link. There are exhibits and a film, as well as free lectures when court is not in session; no reservations necessary.

The International Spy Museum

Even in a city brimming with free public museums, the privately owned International Spy Museum packs in a steady stream of secret-agent wannabes.

The museum features the largest collection of international espionage artifacts ever placed on public display, including concealment devices, sabotage weapons, cipher machines, secret writings and microdots. The multimedia stories of those who actually used these objects in undercover missions around the globe and throughout history are thrilling, if chilling.

Visitors assume clandestine identities and attempt to maintain their covers while immersing themselves in this highly interactive museum. The museum experience concludes with a film about the significance of intelligence in the 21st century.

The International Spy Museum even conducts tours in and around the District of Columbia -- "spy capital of the world" -- and regularly features speakers who share their expertise on a wide array of espionage-related topics.

National Archives and Records Administration

Here, among more than 10 billion paper records, 30 million photographs and almost 3 million maps, you'll find everything from the deed for the Statue of Liberty and childhood photos of presidents to letters to the presidents; among them, a note dated 1940 and penned by a 12-year-old: "My good friend Roosevelt," was the surprisingly informal salutation. "If you like, give me a ten dollars bill green american, in the letter, because never, I have not seen a ten dollars bill green american and I would like to have one of them." It was signed with a flourish: "Castro, Fidel Castro."

A permanent exhibit called Public Vaults offers a truly voyeuristic experience. Read Abraham Lincoln's telegrams to his generals, memos from a 1952 Air Force study of UFO sightings, and immigration papers for Albert Einstein and Alfred Hitchcock. Listen to parts of the actual conversations that took place in the White House during the Cuban Missile Crisis, and peek at original patent drawings for such things as the typewriter, pencil and phonograph. All encompass the raw materials of American democracy.

The Smithsonian Institution

The world's largest museum complex (17 museums plus a zoo) encompasses the National Air and Space Museum, National Zoo and National Museum of Natural History, to name an ever-popular few of the Smithsonian Institution's attractions.

With 126 million specimens in its collection the National Museum of Natural History is the most visited natural history museum in the world. Featured in its Dinosaur Hall is a newly remounted Triceratops; this exhibition shows for the first time an accurate dinosaur skeleton in virtual motion. 

At the 163-acre National Zoo, a home to more than 400 animal species and visit the giant panda cub 'Bei Bei' before he leaves.

The Air and Space Museum exhibition, "America by Air," presents an expanded history of commercial air travel, from early attempts to form airlines only a few years after the invention of powered flight to the commercial challenges and technical sophistication of the 21st-century jet age.

The Smithsonian Institution Building, also known as "The Castle," is situated centrally on the Mall. A royal repository of all things Smithsonian, it's worth a visit for maps and current schedules of free programs, including films and lectures.

The White House

The White House never promised you a rose garden: It simply does not offer easy access to its formal rooms. That said, self-guided tours here are free, and well worth the required hoop-jumping: You must be part of a group of 10 or more, and you must submit a request through your member of Congress. Requests may be made up to six months in advance. You'll learn the date and time of your tour approximately one month in advance of the requested date, and this is subject to cancellation, of course.

Difficult as it is to secure entrance to the White House on any old day of the year, the two most stunning -- and popular -- times to visit are the spring and holiday seasons. The Annual White House Spring Garden Tour, an April tradition since 1972, is open to the public. Timed tickets are distributed by the National Park Service on the mornings of tour days. Visitors may view the Jacqueline Kennedy Garden, Rose Garden, Children's Garden and South Lawn of the White House.

The White House staff starts working during the summer months to formulate ideas for that year's holiday theme and decorations -- and that's just about when you need to get your request in for a December tour.

The White House Visitor Center features information about the White House architecture, furnishings, first families, social events, etc.

MORE: Visit the Martin Luther King, Jr. Memorial