In 1961, the financially strapped Pennsylvania Railroad announced it had sold the air rights above Penn Station. The company would tear down what had once been its crowning jewel to build Madison Square Garden, a high-rise office building and sports complex. Demolition began on October 28, 1963 and would continue for the next three years.

Go underground in the MTA's East Side Access caverns and tunnels - just one of the projects in the MTA's portfolio of $18 billion of construction - which will connect Long Island Railroad trains directly to Manhattan's Grand Central Terminal.

Excavation for the Pennsylvania Railroad's tunnel project was done by hand labor, with workers typically using a spade or pneumatic hammer. Excavation workers, called “sandhogs,” faced many dangers working in a confined space. Equipment was constantly moving in and out along with muck carts full of tons of mud and rock—and there was nowhere to run if things went awry.

Over 500 buildings were initially cleared for Penn Station’s construction, an area equal to two city blocks, or 28 acres. Crews worked day and night to build the train yard below ground, excavating tons of earth from the construction site. Avenues, buildings, and elevated railroads around the construction had to be propped up while workers excavated around the underground infrastructure.

Work never stopped on the Pennsylvania Railroad’s tunneling projects; there were three 8-hour shifts a day, 7 days a week. As the workers dug under the river bed, compressed air was pumped in to keep the water out of the tunnels. To bore under the river, the engineers used a Greathead shield, a steel cylinder with a diameter of 23 feet that weighed nearly 200 tons.

Masonry work began on Pennsylvania Station in 1908, and the grandeur of architect Charles McKim’s design began to take shape. Penn Station took four years to build and used 27,000 tons of steel, 500,000 cubic feet of granite, 83,000 square feet of skylights and 17 million bricks. Pennsylvania Station opened to the public in 1910.

The East River flowed over a mix of gravel, clay, sand, silt and bedrock. When sandhogs hit pockets of sand and gravel, there was a risk of air leaking from the tunnels. Workers were constantly on the alert for a whistling sound—a sign that compressed air was escaping and might at any moment punch a hole through the riverbed, known as a blowout. These blowouts were costly and often deadly.

In an era in which cold-blooded killers such as Jesse James and the Younger Brothers terrorized the American West, Butch Cassidy, the Sundance Kid and their Wild Bunch gang took a smart and methodical approach to bank and train robbery.

Separate fact from fiction regarding the bank robbers whose exploits captivated America.

What is it like to be cut off from your faith and your family? The Amish: Shunned follows seven people who have chosen to leave their closed and tightly-knit communities for the outside world, knowing they can never return. Each has paid deeply for their decision. Estranged form loved ones, these former Amish find themselves struggling to make their way in modern America.

Paul's parents became Amish when he was a boy. He was shunned as an adult. "We had no idea what it meant to be Amish. We thought a clothes change and probably a little more, but we had no idea how much more." The Amish: Shunned premieres on PBS American Experience February 4, 2014.

"In the dominant culture of America, I would have been the good kid -- putting myself through college and working full time, but to the Amish I was a little bit of a rebel. I don't really know how I would do it differently if I had it to do over, but I wish somehow it wouldn't have to be like that." Naomi left her Amish family to become a nurse.

"When we lose obedience, we lose the church. Amen." What is shunning? 2012's The Amish only touched on the practice, but this follow up documentary explores shunning more deeply, interviewing both current and former Amish people. The Amish: Shunned premieres on PBS February 4, 2014.

Follow seven former Amish people who have paid deeply for their decision to leave their closed and tightly-knit communities for the outside world, as they struggle to make their way in modern America estranged from loved ones.

"And I had been seeking God from the age of ten to the age of 41. Thirty years time. There was still that emptiness, and I came to the realization that there has to be more in life than what I am experiencing. There simply has to be more." The Amish: Shunned premieres on PBS American Experience on February 4, 2014.

A profile of Jan, who became Amish as an adult with her husband and children, but they were later shunned.

"I worked in the city for two years. I got used to city life - you know, the throb, the heartbeat of the city, the sirens blasting - and I liked it. But the city could be so full of people, and you could be so lonely. Everybody was in a hurry, everybody had a place to go." The Amish: Shunned premiers on American Experience/PBS February 4, 2014.

"For me, I wanted to experience a different life. I wanted to go out and drive a truck, or something like that. I just thought that would be cool. Back then, that was everything to us. To have phones, radios and stuff like that - of course our parents, they didn't like that." Levi left his Amish family when he was 17. See his story in The Amish: Shunned on American Experience PBS February 4.

"I was letting people down, especially my mother. At that time, people could not ask me specifically about my family or about my background without me bursting into tears." The Amish: Shunned premiered on PBS American Experience February 4, 2014.

"The last time I left, the seventh time, I knew I would never, ever return that day. Cried like a baby. Tried to leave three notes, ripped 'em all up. I realized no matter how hard I tried to explain, nobody would understand." Watch a profile of Joe, who first left his Amish family when he was 16 years old.