Today, the first day of African-American History Month in the United States, is the anniversary of a modest, yet momentous, event that would energize black Americans' fight for civil rights.

On February 1, 1960, in Greensboro, North Carolina, three students from the historically black college in town employed a protest tactic called the sit-in. Dressed in their Sunday best -- suits, dress shirts, and ties -- they took seats in the previously all-white seating area at the Woolworth variety store's lunch counter.

Nobody would serve them, and they were ordered out. When they quietly refused, the owner closed the store.

The next day, ignoring a new sign in the window that read "We Reserve the Right to Service the Public as We See Fit," they and even more students returned and took seats. Police were called, and the students were arrested on trespassing charges and taken to jail.

Even though the Supreme Court had ordered U.S. public schools desegregated six years earlier, public accommodations such as lunch counters and bus terminals were still separated by race in many towns.

The events in Greensboro inspired a wave of sit-ins throughout the South, in particular. There were 120 in September 1961 alone.

Demonstrators often sang "We Shall Overcome," an anthem of the civil-rights movement, as they were hauled off to jail. Students and civil-rights activists, black and white, crowded the jails of southern towns rather than pay fines for creating a public disturbance. Ultimately, the U.S. Congress passed the Civil Rights Act of 1964, which barred racial discrimination by hotels and restaurants.

Sit-ins are still occasionally staged in labor disagreements and on college campuses, but none has been as influential to the public life of the nation as the sit-down in Greensboro, North Carolina, that February day 47 years ago.