After three civil rights workers went missing in Mississippi on June 21, 1964, Rita Schwerner (the wife of missing Mickey Schwerner) played an important role in getting the press and the nation to pay attention to the case. "Freedom Summer" premieres on American Experience PBS June 24 at 9/8c.

"Is it responsible to bring all those kids into the state, most of whom are probably far too naive to understand what they were getting into in terms of the violent nature of the place." Watch "Freedom Summer" premiering June 24, 2014 on American Experience PBS.

Fannie Lou Hamer helped fight for better representation among Mississippi Democrats in 1964. Congressman Adam Clayton Powell of New York City asked for compromise. He didn't know who Fannie Lou Hamer was. Watch "Freedom Summer" on American Experience PBS on June 24, 2014.

Former sharecropper Fannie Lou Hamer's Congressional testimony is so powerful that President Johnson calls an impromptu press conference to get her off the air. But his plan backfires. Watch "Freedom Summer" on American Experience PBS on June 24, 2014.

"People in the movement were willing to die, but we didn't want to die in obscurity. So if we brought in students, their colleges, their parents would focus on Mississippi." "Freedom Summer" premieres on American Experience PBS on June 24.

"They became the closest thing to being a part of the black community as anybody can be because they had no choice." Watch "Freedom Summer" premiering June 24, 2014 on American Experience PBS.

"I went downtown one day, and friends that I had known for 10 years would turn and walk away from me, or hang their heads. Some would speak and walk on as if I had leprosy or something." Watch "Freedom Summer" on American Experience PBS on June 24 at 9/8c.

"I wish to become an active participant rather than a passive onlooker. As my husband and I are in close agreement as to our philosophy in the Civil Rights struggle, I wish to work near him in whatever capacity I may be most useful. My hope is to someday pass on to the children we may have a world containing more respect for the dignity and worth of all men than that world which was willed to us."

During training before Freedom Summer in 1964, tension between the mostly-white volunteers and the mostly-black SNCC staff became evident immediately. "We have to know you. We have to love you, but we don't understand you." "Freedom Summer" premieres on American Experience PBS June 24, at 9/8c.

Local Mississippi leadership prepared themselves psychologically and militarily for Freedom Summer. The Ku Klux Klan rose up as one that April. Mississippi was on a hair trigger. Watch "Freedom Summer" on American Experience PBS on June 24, 2014.

"The Citizens' Council was doing everything the Ku Klux Klan would have done. [...] I joined it because I believed in what they were doing and I believed in trying to preserve the society in which we lived." Watch "Freedom Summer" premiering June 24, 2014 on American Experience PBS.

Folk singer Pete Seeger was performing for a Meridian, Mississippi church congregation when he got word that the bodies of missing civil rights workers Andrew Goodman, Michael Schwerner and James Chaney had been found. American Experience interviewed him about this experience in April 2013. "Freedom Summer" premieres on PBS June 24, 2014.

In 1964, a group of civil rights organizations hosted The Mississippi Summer Project, a campaign that would later become known as "Freedom Summer." "It is very important to me that I play my role in civil rights for the U.S. and most of all for myself," wrote one volunteer. "Freedom Summer" premieres on American Experience PBS on June 24 at 9/8c.

"And then looking up and seeing Ben Chaney. James Chaney's little brother. I lost it. I totally just lost it." "Freedom Summer" premieres June 24, 2014 on PBS.

Over 10 memorable weeks in 1964 known as Freedom Summer, more than 700 student volunteers from around the country joined organizers and local African Americans in a historic effort to shatter the foundations of white supremacy in Mississippi, then one of the nation’s most viciously racist, segregated states.

On August 6, 1964 the Mississippi Freedom Democratic Party held a statewide convention to elect 68 delegates to attend the Democratic National Convention later that month. It was Mississippi's first integrated delegation. Watch "Freedom Summer" on American Experience PBS on June 24, 2014.

In Freedom Schools across Mississippi, Freedom Summer workers and volunteers taught "African American History, Civics, African Culture, African Dance. They were learning black history that they were reading books that'd been written by blacks that they'd never heard of." "Freedom Summer" premieres on American Experience PBS June 24 at 9/8c.

Half a million people pass through New York City's Penn Station every day. During rush hour, a train arrives at a platform every 58 seconds. Phil Kaplan has worked for Amtrak for 37 years, and he takes us for an unusual behind the scenes look at the Central Control room.

Like engineering? Explore the Engineering Map of America and see how the most significant feats of science and technology across the US have transformed the landscape. Contribute your own photos and videos at pbs.org/engineeringmap, and download the Mapping History iPhone app!

The Pennsylvania Railroad built tunnels under New York City's Hudson and East Rivers, connecting New York with New England, and terminating in one of the greatest architectural achievements of its time, Pennsylvania Station. It covered nearly eight acres, extended two city blocks, and housed one of the largest public spaces in the world. But 53 years later, the monumental building was destroyed.