The Washington Monument sits on one end of the National Mall, with the Capitol on the other end in Washington D.C. The monument, one of the city's earliest attractions, was built to honor George Washington, the first U.S. president, and was finished in 1884.
The plaster model of the Statue of Freedom, which was used to cast the statue atop the U.S. Capitol Dome, and other statues are on display in the Emancipation Hall of the Capitol Visitor Center, which opened in 2008.
American sculptor Thomas Crawford created the model in 1858. It was shipped in five separate pieces from Crawford's Rome studio.
The Robert and Arlene Kogod Courtyard, with its elegant glass canopy designed by world renowned architect Norman Foster, is at the historic Patent Office Building that houses the Smithsonian American Art Museum and the National Portrait Gallery.
Foster worked with the Smithsonian to create an innovative enclosure for the 28,000-square-foot space at the center of the building that is sensitive to the historic structure. The "floating" roof does not rest on the original building, which was built in phases between 1836 and 1868.
In the spring, blooming cherry trees frame the front of the Thomas Jefferson Memorial at the Tidal Basin in Washington, D.C. The memorial is modeled after the Pantheon in Rome.
The pillars that represent different states of the U.S. lie at the World War II Memorial. The memorial, which commemorates the sacrifice and celebrates the victory of "the greatest generation," was designed by Friedrich St.Florian and opened to the public in 2004.
The Franklin Delano Roosevelt Memorial near the National Mall traces 12 years of U.S. history with four outdoor rooms, each one devoted to one of FDR's terms of office and feature a sculpture inspired by him. Here, at the beginning of the memorial, is a statue showing Roosevelt seated in a wheelchair like the one he used.
The National Cathedral is the sixth largest cathedral in the world. It was designed in an English Gothic style and features gargoyles, angels, mosaics and more than 200 stained glass windows. There is even a sculpture of Darth Vader on top of the cathedral's west tower.
Officially named the Cathedral Church of Saint Peter and Saint Paul, it's a cathedral of the Episcopal Church, but it honors all faiths.
Tourists walk among the blooming tulips in Lafayette Park across from the White House. Mild temperatures in the spring often bring tourists out in great numbers.
U.S. park rangers dressed in period costumes guide "The Georgetown" up the Chesapeake and Ohio Canal using mules for power during the first canal tour of the season in the Georgetown section of D.C. The Georgetown is an 1870s-period replica used by the park service for tours that depict the history of the canal and the families who lived and worked on it.
When Union Station was completed in 1908, it was one of the largest train stations in the world -- if put on its side, the Washington Monument could lay within the station's concourse. It is considered one of the best examples of Beaux-Arts architecture.
In the 1980s, the building was redeveloped as a bustling retail center and intermodal transportation facility. It currently houses Amtrak headquarters and more than 130 shops and restaurants.
Aircraft are displayed in the James S. McDonnell Space Hangar at the Smithsonian National Air and Space Museum's Steven F. Udvar-Hazy Center in Chantilly, Va. The hangar features hundreds of artifacts installed illustrating its four main themes: rocketry and missiles; human spaceflight; application satellites and space science. The centerpiece of the hangar is the Space Shuttle Enterprise.
A railcar is part of the permanent exhibit at the U.S. Holocaust Memorial Museum. The exhibit features more than 900 artifacts, 70 video monitors and four theaters, and includes eyewitness testimonies and historic film footage.
Some of the more than 53,000 names of U.S. casualities carved into the Vietnam Veterans Memorial are shown here. The memorial is made up of two black granite walls that are almost 247 feet long; each wall consists of 72 panels. The design by Maya Lin initially sparked controversy but is now recognized for its simple and reflective beauty.
A sentinel from the elite 3rd U.S. Infantry marches as the sun rises above the Tomb of the Unknowns on Aug. 26, 2009, at the Arlington National Cemetery in Arlington, Va. More than 300,000 veterans from all of the nation's wars are buried on the grounds.
The Tomb of the Unknowns, where three unknown servicemen are buried, is one of the most visited sites at the cemetery.
An untitled aluminum-and-steel mobile by Alexander Calder hangs in the National Gallery of Art. The gallery got its start when industrialist and philanthropist Andrew W. Mellon donated his vast art collection to the nation upon his death in 1937. Mellon's gift also attracted others to donate art to the museum, whose mission is to serve the United States by preserving, collecting, exhibiting and fostering an understanding of art.
The International Spy Museum is the only public museum in the U.S. dedicated to espionage. It includes the work of famous spies and pivotal espionage actions that shaped history.
At left is a glove shapeed pistol. On the right, is a replica of Cher Ami, the U.S. Signal Corps photo pigeon that was awarded the "Croix de Guerre" by the French government in World War I for heroic service after flying wounded over France for 25 miles in 25 minutes. Cher Ami was equipped with an automatic camera that was taking battlefield photos.
The Smithsonian National Museum of the American Indian is the first national museum dedicated to the perservation, study, culture and history of Native Americans. The museum's massive collections include more than 800,000 works of aesthetic, religious and historical significance and span all major culture areas of the Americas.
Visitors tour the 9/11 Gallery, which includes a piece of the radio tower from the top of the North Tower of the World Trade Center and front pages of newspapers from around the world, at the Newseum, a 250,000 square-foot museum dedicated to news. The gallery also includes first-person accounts from reporters and photographers who covered the story.
People look at the U.S. Capitol at sunset. Around the world, the building, which houses the U.S. Congress, is a symbol of America's democracy. It also includes an important collection of American art and has important architectural significance.
Sunlight illiminates the dome of the U.S. Capitol. In the eye of the dome is a fresco by Constantino Brumidi called "Apotheosis of Washington," which sits 180 feet above the Rotunda floor.
Park ranger Jeff Leary tells the story of the assassination of Abraham Lincoln at the Ford's Theatre. President Lincoln, who ended slavery in the U.S., was assassinated in the box, seen in the background, by John Wilkes Booth at the theatre on April 14, 1865, while he was watching the play, "Our American Cousin."
The Smithsonian Museum of American History is a treasure trove of artifacts from American life, history and pop culture. The ruby slippers worn by Dorothy in the 1939 movie "The Wizard of Oz," left, and President Lincoln's top hat he was wearing when he was shot are included in the display.
People walk around the Apollo 11 Command Module "Columbia" on display at the National Air and Space Museum on July 16, 2009. The museum has the world's largest collection of historic aircraft and spacecraft among some 50,000 artifacts, ranging from Saturn V rockets to jetliners to gliders to space helmets to microchips.
A vendor puts out fruit samples on Aug 1, 2009, at Eastern Market, where consumers can find a large variety of fresh local fruits and vegetables, flowers, delicatessen, meat, cheese, poultry, bakery and dairy products. Eastern Market, established in 1873, is one of the few public markets left in Washington and the only one retaining its original public market function.
A middle-school student views the original U.S. Constitution at the National Archives, billed as the "nation's record keeper." The archives not only house the Bill of Rights and the Declaration of Independence, but it also includes military records and naturalization papers.
Thousands of tourists visit the Lincoln Memorial each year. The memorial, which honors President Abraham Lincoln, sits prominently on the western part of the National Mall and offers great views of the other presidential sites. It includes a large sculpture of Lincoln and inscriptions of two of his speeches, "The Gettysburg Address" and his "Second Inaugural Address."
Nationals Park is home field for the Washington Nationals major leauge baseball team. The park, which opened in 2008, is the first major U.S. stadium that is certified "green." It also has 4,500-square-foot high-def scoreboard and more than 600 linear feet of LED ribbon board along the inner bowl fascia.
A candle sits in a lamp lighting the way for guests arriving to George Washington's Mount Vernon estate as Ben Schulz, left, and Steve Stuart wait for the gates to open Dec. 4, 2004, in Mount Vernon, Va.
The estate, Washington's former home, is 16 miles south of D.C. on the banks of the Potomac River. Visitors can see 20 structures and 50 acres of gardens as they existed in 1799, a museum, the tombs of George and Martha Washington, and his greenhouse.
The U.S. Marine Memorial, left, and the Washington Monument, center, are silhouetted against the sky as the sun rises over D.C.
Fireworks explode over Washington as the United States celebrates its 234th birthday, July 4, 2010. Seen from left is the U.S. Capitol, Washington Monument and Lincoln Memorial.