From the moment workers started clearing away rubble from the collapsed towers of the World Trade Center, New Yorkers and other Americans began debating what kind of memorial would best honor those who died in the terrorist attacks of September 11, 2001. A park? A boulevard? Reflecting pools?

To decide these questions, judges of an international competition spent eight months reviewing more than 5,000 proposed designs. In the end, they chose "Reflecting Absence," created by designers Michael Arad and Peter Walker. The design is shown at the right; click on the image to see a larger view. Even after the intense competition, the selected memorial still evokes controversy. For perspective on the merits of the memorial's design, we offer this review of other memorials in the United States. We hope they may reveal which memorials succeed, and which don't.

USS Arizona Memorial
The USS Arizona Memorial commemorates the Americans who lost their lives during the surprise air attack on Pearl Harbor by Japanese military forces on December 7, 1941. Like the attack on the World Trade Center, the Pearl Harbor attack shocked the nation so profoundly that a memorial at the site was inevitable. In 1962, when the USS Arizona Memorial was finally completed, it met with widespread criticism for its seemingly "crushed" center. Some compared it to a "squashed milk carton," according to Jan-Peter Preis, the son of the late architect Alfred Preis, who designed the structure. The elder Preis once explained that the structure sags in its center but "stands strong and vigorous at its ends," to express "initial defeat and ultimate victory." The memorial floats on the water, straddling the sunken hull of the USS Arizona, one of the 21 ships that were sunk or damaged in the attack. Hundreds of U.S. servicemen went down with the Arizona and remain buried at sea. A shrine in the memorial offers a view of the ship's hull 2.4 m (8 ft) below the surface of the water. Despite the initial chilly reception for the memorial, it has become Oahu's biggest tourist attraction, drawing 1.5 million visitors annually. 

Thomas Jefferson Memorial
The Thomas Jefferson Memorial, completed in 1943 in Washington, D.C., was designed in a classical style, befitting a man who so revered Greek and Roman classical architecture. Jefferson, the consummate American renaissance man, was not only a political philosopher, musician, book collector, scientist, horticulturist, diplomat, inventor, and third president of the United States--he was also an architect. Judging by the buildings he designed for the University of Virginia and by the design of his own house, Monticello, it's easy to think that Jefferson would appreciate the classical lines of his memorial, designed by architect John Russell Pope. A bronze statue of Jefferson stands inside the structure, facing the White House. Selected quotations of his writings on freedom and democracy are inscribed on the marble walls. The grand structure is prominent even among all the other neo-classical structures of the capital. Nevertheless, visitors in the springtime seem just as enamored of the blossoming cherry trees surrounding the building as they are of the memorial itself.

Vietnam Veterans Memorial
One of the most celebrated American monuments of the late 20th century, the Vietnam Veterans Memorial in Washington, D.C., generated intense controversy even before its construction began. Most of the controversy was directed at the selection of the memorial's architect, Maya Lin, because she was an inexperienced young undergraduate at Yale University when she won the design competition. Many also criticized the somber tone of the design, which called for two starkly minimal, highly polished black slabs of granite to cut in the ground, as though the memorial itself were half-buried. Few knew what to make of the fact that the only ornamentation of the stone would be the engraved names of the more than 58,000 Americans who died or are missing as a result of the Vietnam War (1959-1975). When the memorial was finally unveiled in November 1982, most of the criticism ended. Visitors to the memorial--veterans, relatives of the dead, friends, and others--were profoundly moved as they saw their own faces reflected in the polished stone while searching for familiar names among the dead and missing. The memorial now serves as a kind of Wailing Wall for a nation still grappling with its conflicted history in Vietnam. Those still critical of the stark memorial were likely mollified by the addition in 1984 of a more traditional, heroic bronze statue by Frederick Hart entitled Three Servicemen and by the Vietnam Women’s Memorial, a bronze sculpture by Glenna Goodacre, added in 1993.

Mount Rushmore National Memorial
One of the most audacious public monuments in the United States is the Mount Rushmore National Memorial, in South Dakota and designed by sculptor Gutzon Borglum. Between 1927 to 1941 workers armed with drills and dynamite carved giant busts of U.S. presidents George Washington, Thomas Jefferson, Abraham Lincoln, and Theodore Roosevelt into the rim of Mount Rushmore 150 m (500 ft) above the valley floor. The faces--each more than 20 m (60 ft) tall--seem to gaze serenely across South Dakota's Black Hills and, by suggestion, across the nation. To some, Mount Rushmore honors the birth, growth, preservation, and development of the United States. To others, it's an abominable scarring of natural beauty. Still others like to think of it as the granddaddy of America's kooky roadside attractions. Most seem to agree, however, that it made an unforgettable setting for Cary Grant as he was chased across the giant mountain busts in Alfred Hitchcock's North by Northwest.

Lincoln Memorial
Designed to resemble a classical Greek temple, the Lincoln Memorial may come closer to deifying its subject than any other public monument in the United States. The memorial, which overlooks the Potomac River in Washington, D.C., is widely admired for expressing president Abraham Lincoln's steel-eyed resolve to unify the nation and lead it out of the American Civil War. The focal point of the memorial's interior is a grand marble statue of Lincoln, seated as though on a throne. On the wall behind the statue are inscribed the words, "In this temple, as in the hearts of the people for whom he saved the Union, the memory of Abraham Lincoln is enshrined forever." Since its dedication in 1922, the memorial has also cast its beatific glow on a number of other civil-rights heroes and political leaders who have spoken on the site. In 1939 African American opera singer Marian Anderson sang to 75,000 people from the steps of the Lincoln Memorial after the Daughters of the American Revolution denied her the right to perform in Constitution Hall. And in 1963, during the March on Washington for civil rights, Martin Luther King, Jr., delivered his famous "I Have a Dream" speech at the memorial.

Franklin D. Roosevelt Memorial
The Franklin D. Roosevelt Memorial sprawls across 7.5 acres of the National Mall in Washington, D.C. It is divided into four outdoor "rooms," representing Roosevelt's four terms as president of the United States. Several sculptures on the site depict the president and many of the notable events that occurred during his terms in office. But despite the vast expanse of the memorial, the focal point for most Americans has become one life-sized bronze statue by sculptor Robert Graham that depicts Roosevelt in a wheelchair. (Roosevelt contracted polio in 1921 and conducted most of the work of his presidency while seated in a wheelchair.) Roosevelt himself would almost certainly have disapproved of the statue--he went to great lengths to mask his disability, and no pictures were ever published during his lifetime that depicted him in a wheelchair. Members of the disabled community view the sculpture as a triumph, however, because it offers the public a chance to see that one of the nation's greatest presidents was also disabled.

Coit Tower
Surely one of the most idiosyncratic memorials in the country, San Francisco's Coit Memorial Tower honors the city's volunteer firefighters in the form of a giant fire hose nozzle perched atop the city's Telegraph Hill. Completed in 1932, the tower is named after Lillie Hitchcock Coit, who left $118,000 for a monument to her beloved city. Coit was proud of her reputation as a wild woman in the days of the Gold Rush, and she made a show of drinking, smoking cigars, gambling, and dressing like a man. It's said that she loved the city's volunteer firefighters as much as she loved San Francisco itself, so Coit Tower made a fitting memorial to them both. With its spectacular views and the legends about its colorful benefactor, the 64-m (210-ft) Coit Tower seems to symbolize both its host city's beauty and its embrace of all things eccentric.