In 1936, a Harlem postal worker named Victor Green published a book that would go on to become a vital companion for African-American motorists: the "Green Book."

How the 'Green Book' Helped Black Motorists Travel Safely (2:41)

Standing in the Roman senate, Octavian read out the shocking details of Mark Antony's will. It was a devastating revelation that immediately gave the young schemer a major advantage over his soon-to-be disgraced rival.

How Octavian Succeeded in Discrediting Mark Antony (3:18)

When Octavian emerged as the sole ruler of Rome, he immediately began a sophisticated PR campaign to clean up his image. He ditched the military regalia and presented himself as a man of peace.

How Octavian Successfully Rebranded Himself (3:30)

The strict laws of Prohibition were selectively enforced, and the brunt of their legal impact fell on minority and working-class groups while vigilante groups used "Prohibition enforcement" as cover. In this way, Prohibition helped fuel the re-emergence of one of the most notorious hate groups of all time: the KKK.

How Prohibition Led to the Revival of the Ku Klux Klan (3:01)

From Radio City Music Hall to '30 Rock,' Rockefeller Center was a construction project befitting of the city's ambition. But its build was an epic affair—and came with an eye-watering price tag.

The Staggering Price Tag of NYC's Rockefeller Center (1:42)

While stars like Jimmy Stewart and Clark Gable enlisted and served during WWII, directors like John Ford would bring military footage of the Pacific conflict straight to American viewers.

How Hollywood Encouraged Recruitment for WWII (2:38)

When you look at the sheer scale of her athletic achievements, it's a wonder she's not better known today: boxing star, three-time Olympic medalist, and one of the best women's golf players of all time.

The Most Famous Female Athlete You've Never Heard Of (1:37)

The Smithsonian curator of political history talks with the co-founder of One Common Unity about creativity, education and solving the world’s biggest problems

The Long Conversation 2018: Jon Grinspan Interviews Hawah Kasat (11:57)

The New York Times columnist and the Smithsonian curator of political history talk about what we can learn from partisan struggles of the past

The Long Conversation 2018: David Brooks Interviews Jon Grinspan (11:36)

On September 2, 1945, Japan delivered its unconditional surrender in WWII. Twelve million American troops went home as civilians, to work and raise families--ushering the U.S. into a new age of global leadership.

Japan's Surrender in WWII Ushered in a New World Order (2:06)

Two rival explorers have teamed up on a very special project in the Baltic sea. Their aim is to locate and explore the wreck of one of the most historic ships in Swedish history: Mars.

Team of Explorers Uncover Famous Sunken Ship (3:23)

The AC-130 is the world's biggest flying artillery gunship - nicknamed 'Hell in the Sky.' With three side-firing weapons, a 25mm Gatling gun, a 40mm Bofors cannon, and a 105mm howitzer, it's easy to see why it got its name.

Deadly AC-130 Gunship in Action Firing All Its Cannons (3:07)

It's November 2001, and lieutenant colonel Allison Black is a navigator on an AC-130 gunship flying over Afghanistan. She recounts a typical combat mission during operation Enduring Freedom.

AC-130 Gunship Navigator Recalls Taliban Combat Mission (2:56)

The USS Guadalcanal has spotted a German sub in the waters off the coast of Madeira. They immediately order a strike with the navy's new and devastating weapon: the hedgehog.

A U.S. Warship Fires an Anti-Sub Weapon on a German U-Boat (4:24)

Allied POWs rescued in the South China Sea have an incredible story to tell. They'd been kept in a secret prison camp in Thailand, where their Japanese captors forced them to build a railroad from Thailand to Burma.

These POWs Were Forced to Build the Bridge Over River Kwai (2:34)

Domesticating horses gave the ancient Scythian nomads speed and mobility. But they were also a vital source of nutrition, providing both meat and milk.

Why Horses Are So Vital in the Lives of These Nomads (1:57)

After a long-drawn out conflict in the Pacific, the troops needed a morale boost. And the United Service Organizations provided it in spades, thanks to spectacular shows by Hollywood legends like Bob Hope and Joe E. Brown.

Why USO Tours Were Vital for Troop Morale in the Pacific (2:01)

In the 1560s, Eric XIV of Sweden was determined to change the way naval battles were fought. The result was Mars: a giant of a warship that would rely on artillery and firepower to devastate her rivals.

This Swedish King Built a Warship That Redefined Naval Combat (3:21)

It's November 1943 and a German U-boat has been brutally damaged in a fight with British warships and is limping its way to port. But the sub's onboard batteries are impaired - which means it can't dive to evade enemy ships.

This Badly Damaged German U-Boat Can't Dive for Cover (3:45)

A reactor failure on a K-19 nuclear sub in 1961 ended up killing several crew members due to radiation poisoning. It was a horrifying episode that would have ramifications for a later, top-secret Soviet operation.

How a Nuclear Sub Disaster Impacted This Soviet Operation (3:36)

A Soviet B-59 submarine has been spotted off the southeast coast of the U.S. mainland in 1962. The White House draws up a plan, but they don't know that this sub is carrying a devastating nuclear weapon on board.

What the U.S. Didn't Know About This Soviet Sub Near Cuba (3:28)

The USS Barb had an unusual target in its sights in 1945 - one that wasn't even in the water. It was a Japanese supply train on the island of Karafuto.

This U.S. Sub Launched an Attack on a Japanese Train (3:07)

A British frigate fires on the USS Constitution - but its shots either miss or rebound off its tough oak hull. It's a feat of resilience that earns the American warship her proud nickname: Old Ironsides.

This 1812 American Frigate Could Take a Direct Cannon Hit (3:20)

During WWII, Nazi forces were preparing to take the coastal city of Tobruk and tighten their grip on North Africa. In response, the Allies turned their attention to another key strategic location: the tiny Mediterranean island of Malta.

This Tiny Island Was Key for Allied Forces to Secure North Africa (2:21)

On February 9, 1945, two submarines are poised to engage in a direct, underwater confrontation. It's the first - and only - underwater submarine dog fight in recorded naval history.

Rare WWII Submarine Dog Fight Turns Deadly (3:21)

It's June 1945 and the USS Barb has just launched an unprecedented attack on the factories of the Japanese island of Shari. It's the first time that rockets have ever been launched from a submarine.

The First Submarine to Launch Rockets From Its Deck (2:24)

The British Navy knew it couldn't completely disguise a ship to protect it from attack during WWI. So they turned to 'Dazzle Painting' which sought to disguise a ship's speed and direction.

How the British Navy Camouflaged Their Ships Using Art (2:32)

In 2011, declassified CIA documents shed light on a covert government program dating back to WWII. At its center was a submersible craft built for a hypothetical invasion of Japan.

This Secret Boat Was Built for a WWII Invasion That Never Happened (2:17)

After the Napoleonic Wars caused a shortage of British Oak, frigate builders looked all over the empire for an alternative. They found one in India: a hard, water resistant wood called teak.

Why Shipbuilders Were Forced to Stop Using British Oak (1:30)

The USS Silversides is patrolling the Pacific during WWII when it finds itself in a terrifying situation: one of its torpedoes has jammed and is dangling out in the water, ready to explode.

A Torpedo Malfunction Threatens to Destroy a U.S. Submarine (2:40)