Ronald Reagan left the White House one of the most popular presidents of the twentieth century — and one of the most controversial.

A passionate ideologue who preached a simple gospel of lower taxes, less government, and anti-communism.

In 1988, after two terms in office, Ronald Reagan left the White House one of the most popular presidents of the twentieth century -- and one of the most controversial. One by one, his opponents underestimated him; one by one, Reagan surprised them, rising to become a president who always preferred to see America as a "shining city on a hill."

In a televised address to the nation, delivered on March 23, 1983, President Reagan announced his vision of a world safe from nuclear threat. His Strategic Defense Initiative (SDI), later dubbed "Star Wars" by the press, is an idea that remains controversial to this day.

An epic story of adventure, abandonment and human tragedy, The Greely Expedition tells of an 1881 scientific mission to the Arctic that ended with death and rumors of cannibalism.

Historian Michael Robinson talks about the American scientific landscape in the 19th century and the significance of The Greely Expedition.

On December 10, 1913, after a final push of excavation, the unbroken waterway finally connected the Atlantic Ocean to the Pacific Ocean. The project had taken ten years and more than $350 million. To that date, it was the largest single federal expenditure in history. More than 5,000 workers lost their lives, but the successful completion defined the US as a superpower of the 20th century.

Upon the arrival of new Chief Engineer John Stevens, the rusty and decrepit Panama Railroad was by that time 60 years old. Stevens realized that he was unable to cart out the spoil at the same furious rate that the canal was being dug. He ordered all excavation in Culebra Cut to be temporarily halted and turned his attention toward the repair of the railroad.

In all, approximately 5 million bags and barrels of concrete went into building the Panama Canal's locks, dams, and spillways. The locks were engineered to be hollow and water tight, making them buoyant, so that the weight and pressure on the hinges would be significantly reduced. The locks at Gatun were 80 feet high, completely powered by electricity generated by a nearby hydroelectric spillway.

On November 12, 1904, the first Bucyrus steam shovel arrived in Colón, able to excavate five cubic yards of spoil in a single scoop. Despite the efficiency of the steam shovel, the 50-year old rail system proved incapable of carrying that amount of spoil away.

Stevens realized that building a sea level canal would doom the project to failure. His answer was to build a lock canal -- a highly mechanized and engineered waterway that would raise ships up over the continent through a series of lock chambers, ultimately solving the environmental challenges they were facing.

Mahatma Gandhi's nonviolent movement to free India from British colonial rule inspired American civil rights activists who had immersed themselves in Ghandi's teachings and viewed non-violence as an effective way to challenge the tyranny of the Jim Crow South.

After deciding to participate in the Freedom Rides in May 1961, Jim Zwerg called his parents for support only to be told that he was "killing his father." As a white Freedom Rider, Zwerg was among the first to be attacked and sustained severe injuries.

In the decades after WWII, civil rights leaders relied on legal and legislative challenges to dismantle segregation. But in the early 1960s, activists impatient for change turned to a new strategy: non-violent direct action.

Group singing provided solace for Freedom Riders facing the constant threat of violence. It was also an effective political tool. "Without singing, we would have lost our sense of solidarity," John Lewis says.

This biography of Ulysses S. Grant paints a revealing portrait of one of America's most paradoxical leaders. In 2011 AMERICAN EXPERIENCE rebroadcast this film as U.S. Grant: Warrior, an abridged 90-minute version of the film, focusing on Grant as a Civil War hero and a brilliant military strategist who rose from obscurity to a rank held previously only by George Washington.

The Freedom Riders represented a cross-section of America - black and white, young and old, religious and secular. "The Freedom Rides were trying to say to America: we are a diverse country - let's act like a diverse country, where every part of the diversity is equal, and is treated equally," says Freedom Rider Rabbi Israel Dresner.

In April 1947 sixteen men - eight black and eight white - boarded a bus in Washington, DC to test compliance with a recent Supreme Court ruling that outlawed segregation on interstate bus travel. Their effort blazed a trail for the Freedom Riders who followed in their footsteps nearly fifteen years later.

John Patterson, Governor of Alabama from 1958 to 1963, won election as a staunch segregationist. Patterson discusses his response to the Freedom Rides and his decision to refuse a phone call from President John F. Kennedy when the Freedom Riders encountered mob violence in Birmingham.

A student at Fisk University in Nashville, Diane Nash became the leader of the Nashville Student Movement. Fellow activists John Lewis, Ernest "Rip" Patton, Jr., Rev. James M. Lawson, Jr., and Julian Bond describe her commitment to nonviolence.