While President John F. Kennedy took the lead in establishing the Peace Corps, he wasn’t the first politician to propose an international service organization. One of the idea’s earliest champions was Wisconsin Representative Henry Reuss, who pushed for the creation of a “Point Four Youth Corps” in the late 1950s. In June 1960, meanwhile, Minnesota Senator Hubert Humphrey coined the name “Peace Corps” when he introduced a bill advocating for a program to send “young men to assist the peoples of the underdeveloped areas of the world to combat poverty, disease, illiteracy and hunger.” Neither of the earlier proposals gained traction, but they played a key role in inspiring Kennedy and his staff to begin researching the idea during the 1960 presidential campaign.

At 2 a.m. on October 14, 1960, Senator John F. Kennedy arrived at the University of Michigan near the end of his presidential campaign. The candidate had planned on heading straight to bed, but when he noticed that a crowd of 10,000 students had gathered to greet him, he stepped behind a microphone and gave an unscripted speech. “How many of you who are going to be doctors, are willing to spend your days in Ghana?” he asked. “Technicians or engineers, how many of you are willing to work in the Foreign Service and spend your lives traveling around the world?” Kennedy wouldn’t officially call for a “peace corps of talented young men and women” until two weeks later, but his late-night challenge is now cited as the program’s founding moment. The University of Michigan in Ann Arbor even has a plaque on its campus marking the spot where Kennedy “first defined the Peace Corps.”

By the time he was inaugurated as president, Kennedy’s Peace Corps had become one of the most talked-about aspects of his platform. University students circulated petitions and pledges to serve, and more than 25,000 letters arrived from prospective volunteers. Faced with such an overwhelming response, Kennedy placed his brother-in-law, Sargent Shriver, in charge of a special task force to create the new organization. Shriver and a brain trust of academics issued a report on the program in just a few weeks, and Kennedy officially established the Peace Corps by executive order on March 1, 1961. Work continued at a frantic pace over the next few months as Shriver—the organization’s first director—interviewed applicants and enlisted the participation of foreign governments. By August 30, a little more than seven months after Kennedy’s inauguration, the first contingent of 51 Peace Corps volunteers had already arrived in Accra, Ghana, to serve as teachers.

President Kennedy considered the Peace Corps a Cold War tool to bolster the United States’ reputation and counter the Soviet Union’s influence abroad, but many of his fellow lawmakers were skeptical of what was mockingly called the “Kiddie Corps.” Richard Nixon branded the program a “cult of escapism” and argued that it catered to young men looking to skip out on the military draft. Former President Dwight D. Eisenhower, meanwhile, called it a “juvenile experiment” and suggested that its members should be sent to the moon. Despite the criticisms, the Peace Corps remained popular among college students and young people during its early days. By its fifth anniversary in 1966, it boasted over 15,000 volunteers serving two-year terms in 46 countries.

Since it was founded during the height of the Cold War, the Peace Corps was often subject to speculation that it was a front organization for the Central Intelligence Agency. The Kennedy administration ordered the CIA not to meddle in the Peace Corps’ affairs, but many host countries still believed rumors and Soviet propaganda that the program’s volunteers were undercover spies. In the interest of avoiding any connection to the espionage community, the Peace Corps has always maintained a blanket ban on former CIA employees becoming volunteers. Former members of other intelligence outfits are allowed to serve in some cases, but only after a 10-year waiting period.

Peace Corps volunteers often face extreme conditions while working in remote and undeveloped parts of the world. The organization suffered its first casualties in 1962 when volunteers Larry Radley and David Crozier were killed in a plane crash in Colombia. Since then, around 300 other volunteers have died on duty from car crashes, accidents, sickness, drowning, animal attacks and violent crime. While certain hazards are unavoidable, the Peace Corps often evacuates volunteers from unstable or potentially dangerous parts of the world. In recent years, security concerns have seen it suspend operations in Kazakhstan, Niger, Honduras, Jordan and El Salvador.

The Peace Corps is designed to work in the developing world, but a lone exception to its overseas mandate came in 2005 when Hurricanes Katrina and Rita ravaged the U.S. Gulf Coast. In the wake of the storms, the Peace Corps dispatched nearly 300 veteran volunteers to Louisiana to distribute food, search for survivors and clear debris. The relief efforts marked the first time in Peace Corps history that the organization carried out operations on home soil. Information on fallen Peace Corps volunteers and staff can be found at fpcv.org

The average age of Peace Corps volunteers is 28, but the organization has no rule preventing the middle-aged or the elderly from serving. President Jimmy Carter’s mother Lillian famously joined the Peace Corps at age 68, and roughly 7 percent of all current volunteers are over age 50. As of 2016, the Peace Corps’ oldest active member was Alice Carter, an 87-year-old Boston grandmother serving in Morocco.