215 petitioners, including El Salvador native Enrique Torres Manzano, center, raise their right hands and swear an oath to the United States and become new citizens during a ceremony at the National Archives on Sept. 17 in Washington, D.C. The ceremony was held on the 225th anniversary of the signing of the U.S. Constitution in the Rotunda of the archives which holds the "Charters of Freedom": The Declaration of Independence, the Bill of Rights and the Constitution.

Maria Cruz, center, of El Salvador joins 214 other petitioners seeking U.S. citizenship in saying the Pledge of Allegiance at a naturalization ceremony in the National Archives, in Washington, D.C., on Sept. 17.

U.S. Homeland Secretary Janet Napolitano speaks at a naturalization ceremony on Sept. 17 at the National Archives in Washington, D.C.

A native of Lebanon, Mirna Mumm uses a U.S. flag to hold her hair in place after becoming one of 215 new citizens during a ceremony at the National Archives on Sept. 17 in Washington, D.C.

An illegal dumping area off the New Jersey Turnpike, facing Manhattan across the Hudson River, and north of the land fill area of the proposed Liberty State Park, N.J., is seen in March 1973, and an image from the same vantage point in April 2012 shows the Jersey City and New York City skylines with the green area near Liberty State Park in Jersey City, N.J., in the foreground.

Ongoing urban development and construction on lower Manhattan's West Side is seen just north of the World Trade Center, right, in New York in May 1973. The same site is seen in April 2012.

The Publisher's Paper Company in Oregon City, Ore., on the Willamette River is seen in April 1973 at left. Together with Crown-Zellerbach Corporation, this company led a campaign to clean up the river. The Publisher's Paper Company, now closed, is seen in April 2012, right.

An 'Out of Gas' sign is seen, left, at the gas station at the intersection of SW Jefferson and 18th St. in Portland, Ore., in June 1973, during the fuel shortage. Similar signs cropped up all over the Portland area during the fuel crisis. At right, a restaurant sign on the corner of 18th St. and Jefferson shown in Portland, Ore., with a public transportation stop in the background.

Clark Avenue and the Clark Avenue Bridge in Cleveland, Ohio, looking east from west 13th Street, are obscured by the smoke from heavy industry in July 1973, left. The same view is seen in April 2012.

Trash and old tires litter the shore at the middle branch of the Patapsco River in the harbor of Baltimore, Md., in January 1973. The same location is seen in April 2012.

A sunrise over the Olin-Mathieson Plant on the Calcasieu River in Calcasieu Parish, La., is seen in June 1972, right. The same site is seen, right, April 2012.

At left is contaminated water in a drainage ditch behind the Pittsburgh Glass Company near Lake Charles, La., in 1973. The same location is now overgrown with vegetation in April 2012 at right.

Part of the Olin Mathieson Plant on the far side of Side of Lake Charles, La., is seen in July 1972 at left. People sun themselves, right, near the site of the old Olin-Matheison Plant in April 2012.

Left: This photo, taken between 1972 and 1977 and released by the U.S. National Archives, shows a truck moving through a residential neighborhood on Lovell Street, adjacent to Logan Airport in Boston. The street ends at the Wood Island Transit Station near construction on a building to be leased to the food preparation business for one of the airlines. Right: The residential neighborhood that was once there is gone.

Neighborhood youngsters play in the playground adjacent to Logan Airport at the end of Neptune Road in the East Boston neighborhood of Boston in May 1973, left, and the same site is seen in April 2012, right.

The Metropolitan Boston Transit Authority tracks, crossing across Neptune Road in East Boston, Mass., near Logan Airport in April 1973, left, and in April 2012, right.

The industrialized port area of Corpus Christi, Texas, in November 1972, left, and April 2012.

Left: The Donald Cook Nuclear Power Plant is shown still under construction on Lake Michigan at Bridgman, Mich., in August 1973. Right: The Cook Nuclear Plant in April 2012.

A group of nine men pose in front of a tent with a surveying instrument at left. The two men seated center and right are most likely Frederick W. Door and John W. Donn. The officer seated to the left is William H. Paine who invented the steel tape reel worn by the man standing on the right. Standing second from right appears to be Allan Pinkerton. Photograph from the main eastern theater of war, the Peninsular Campaign, May-August 1862.

Stone church in Centreville, Va. during the Civil War.

Anaglyph stereograph made from digital images of a pair of stereograph negatives (above) of the Petersburg railroad depot in Richmond, Va., during the Civil War.