<P> The Pentagon became a focal point for protests against the Vietnam War during the late 1960s . A group of 2,500 women, organized by Women Strike for Peace, demonstrated outside of Secretary of Defense Robert S. McNamara's office at the Pentagon on February 15, 1967 . In May 1967, a group of 20 demonstrators held a sit - in outside the Joint Chiefs of Staff's office, which lasted four days before they were arrested . In one of the better known incidents, on October 21, 1967, some 35,000 anti-war protesters organized by the National Mobilization Committee to End the War in Vietnam, gathered for a demonstration at the Defense Department (the "March on the Pentagon"), where they were confronted by some 2,500 armed soldiers . During the protest, a famous picture was taken, where George Harris placed carnations into the soldiers' gun barrels . The march concluded with an attempt to "exorcise" the building . </P> <P> On May 19, 1972, the American radicals known as the Weather Underground Organization successfully planted and detonated a bomb in a fourth - floor women's restroom in the Pentagon . They announced it was in retaliation for the Nixon administration's bombing attacks on Hanoi during the final stages of the Vietnam War . </P> <P> On March 17, 2007, 4,000 to 15,000 people (estimates vary significantly) protested against the Iraq War . The protesters marched from the Lincoln Memorial, down Washington Boulevard to the Pentagon's north parking lot . </P> <P> From 1998 to 2011, the Pentagon underwent a major renovation, known as the Pentagon Renovation Program . This program, completed in June 2011, involved the complete gutting and reconstruction of the entire building in phases to bring the building up to modern standards, removing asbestos, improving security, providing greater efficiency for Pentagon tenants, and sealing of all office windows . </P>

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