Dave Roos

Sunk by earthquakes or swallowed by rising tides, these five underwater settlements hold artifacts and clues to ancient life.

From desegregation at Little Rock to MLK's Selma-to-Montgomery march to the Cuban refugee crisis, these are major moments when U.S. presidents have deployed troops in America.

On June 6, 1944, more than 156,000 American, British and Canadian troops executed the largest amphibious landing in history. Five veterans share their stories from that day.

Hungry bears—whether grizzly, black, brown or polar—can be shockingly brutal.

In April 1896, Thomas Edison rented a New York Vaudeville hall to show a film—an event that many consider to be America's first movie theater experience.

These presidential candidates didn't need to secure more popular votes to win election, due to the Electoral College.

These storied rivers have played a big part in American agriculture, ecosystems—and history.

The origin story of the first iPhone reveals that Jobs was just trying to make a really cool phone.

The explorers not only produced maps from their 1804-1806 expedition to the American West, they also recorded some 122 animals new to science.

When scandalous news emerged in the final weeks of these presidential campaigns, election outcomes were at stake.

At the close of the Civil War, people recently freed from slavery in Charleston honored fallen Union soldiers.

Elite Gilded Age families competed for status by building extravagant summer 'cottages' in Newport and throwing lavish parties.

Horses were first introduced to Native American tribes via European explorers. For the buffalo-hunting Plains Indians, the swift, strong animals quickly became prized.

In 1804, Lewis and Clark set off on a journey filled with harrowing confrontations, harsh weather and fateful decisions as they scouted a route across the American West.

As the Donner Party fought to survive in the snowy Sierra Nevada mountains, four brave rescue missions ensured some traumatized members made it out alive.

Among seven Apollo moon landing missions, only one did not land men on the moon.

At the turn of the 20th century, there was life-changing money to be made in operating a “show cave.” Those prospects fueled fierce competition. 

Eyewitnesses of the 1857 Fort Tejon earthquake described fissures tearing open in the earth, rivers changing course, trees being swallowed up by liquefaction and solid ground rolling like waves in the ocean.

When a small, scrappy Mexican force handed the French army a surprise defeat in 1862, the Confederacy was denied a potential ally.

Communist North Korea invaded South Korea in 1950 with the approval of Joseph Stalin and the promise of backing from China.

The ancient office of the pope is rich in symbols and insignia. Here are some of the most visible and meaningful of the papal symbols.

Details around the 1969 police shooting of Hampton and other Black Panther members took decades to come to light.

The Allied invasion of Normandy was among the largest military operations ever staged.

The Founding Fathers had just broken free from one empire, and the idea that foreign power could influence their young democracy was a prominent source of anxiety.

Opportunity in the United States beckoned—but first immigrants from Europe had to endure a grim journey.

Just weeks before the match, Soviet tanks and troops brutally crushed the short-lived Hungarian Revolution.

After infecting millions of people worldwide, the 1918 flu strain shifted—and then stuck around.

The first strain of the 1918 flu wasn’t particularly deadly. Then it came back in the fall with a staggering death toll that eclipsed even the casualties of World War I.

Mexican American families in California secured an early legal victory in the push against school segregation.

In the 1820s, no one had heard about an anti-establishment candidate—until Andrew Jackson's campaign invented it.

With his political career in ruins after killing Alexander Hamilton, Aaron Burr set off to claim lands in the Southwest—and President Jefferson intended to stop him.

Federalism, or the separation of powers between state and federal government, was entirely new when the founders baked it into the Constitution.

Two of Christopher Columbus’ ships were so small that men had no refuge to sleep and poor food storage led to wormy meals.

"I am not the Catholic candidate for president,” JFK declared in 1960. “I am the Democratic Party's candidate for president, who happens also to be a Catholic."

Early versions of a carpet cleaning device were pulled by a horse, but it was a janitor who came up with a portable model you could plug in.

From post-war recessions to the energy crisis to the dot-com and housing bubbles, some slumps have proven more lasting—and punishing—than others.

Gifted photographers and reporters captured images that conveyed the agony and violence of the Vietnam war, and the deep divisions it drove in American society.

Nearly 12,000 helicopters saw action in the Vietnam War and were critical for combat, scouting, rescue missions and more.

People living in this Bronze Age civilization crafted unique objects that shed light on life in ancient China some 3,200 years ago.

From carefully staged speeches to radio to Twitter, U.S. presidents have always leveraged the cutting edge to connect directly with voters.

Some lame-duck presidents and lawmakers managed to pack in major, sometimes stinging initiatives during their final weeks in office.

The town of Ferrara managed to avoid even a single death from the widespread contagion. How did they do it?

Way back in the 14th century, public health officials didn't understand bacteria or viruses, but they understood the importance of keeping a distance and disinfecting.

In the post-Civil War era, when many Americans were reeling from loss, a photographer claiming to capture ghosts on film enjoyed swift business.

The ancient Celts were a widespread group of tribes whose rich culture has been identified through burials, artifacts and language.

The shocking deaths of seven people in the Chicago area from tampered bottles led to a massive recall—and generated fears around candy poisonings.

The wrenching images and first-hand testimonies of Dachau recorded by U.S. soldiers brought the horrors of the Holocaust home to America.

The vibrant network opened up exchanges between far-flung cultures throughout central Eurasia.

Since the Civil War, forces have deployed aerial surveillance gadgets from balloons to robotic dragonflies.

Woodstock 1969 was plagued by stormy weather and technical problems, but it produced a string of musical performances that resonate a half-century later.

To see the epic performances at Woodstock, attendees endured crowds, rain, minimal food and water—and lots of mud.

More than 35,000 volunteers from 52 countries poured into Spain to help fight fascist-backed Nationalists led by Francisco Franco.

The massive British corporation was founded under Queen Elizabeth I and rose to exploit overseas trade and become a dominating global player.

A temporary solution to organize Germany into four occupation zones led to a divided nation under the Cold War.

In the first half of the 20th century, U.S. educators shunned homework. The Soviet Union’s launch of Sputnik 1 changed that.

U.S. Supreme Court justices have generally deferred to precedent, but there have been notable exceptions.

Ancient historians describe Alexander offering prize money to those men who climbed towering cliff faces in the fastest time.

The longest cave system winds for more than 400 miles, but others on the list haven't even been fully explored yet.

From pandemics to wars to natural disasters, these events took the highest tolls on American lives.

The tsunami was the deadliest in recorded history, taking 230,000 lives in a matter of hours.

Charles Richter worked with Beno Gutenberg to develop one of the first data-driven ways of comparing earthquakes.

Alexander used both military and political cunning to finally unseat the Persian superpower.

Neil Armstrong’s celebrated “one small step” was far from the most dangerous maneuver in the effort to send three men to the moon and return them home a week later. See a timeline of the entire mission.

The document was designed to prove to the world (especially France) that the colonists were right to defy King George III's rule.

Tanks—particularly the M1A1 Abrams—proved critical for U.S.-led coalition forces in the Persian Gulf War.

The Yippies found their voice by organizing an absurdist counter-convention—including nominating a pig for president.

Hammurabi's Code may get all the attention, but barley and wool were the mainstays of Babylonian day-to-day life and commerce.

Kingpins like Al Capone were able to rake in up to $100 million each year thanks to the overwhelming business opportunity of illegal booze.

The Kennedy patriarch amassed great wealth partly by selling alcohol, but he also made savvy deals and sales that became extremely lucrative.

The 1980s battle over safety belt laws reflected widespread ambivalence over the role and value of government regulation.

A Senate impeachment trial is modeled on the criminal trial process—except the Supreme Court chief justice presides and senators act as jurors.

Oswald's would-be victim on April 10, 1963, was an ultra-conservative firebrand named Edwin Walker.

After mounting tensions between Catholic nationalists and Protestant loyalists, particularly in Belfast and Derry, violence broke out in the late 1960s.

From the 17th century onward, European and colonial homeowners stashed odd objects in their houses as added security.

The stunning 1974 discovery offered proof that ancient hominins were walking around on two feet some 3.2 million years ago. 

The incidents interrupted Exercise Mainbrace, a massive set of NATO war-game maneuvers.

On the heels of the Great Depression, the federal government under FDR hired young people to work on projects across the country. Here’s what the Corps got done.

During their two-month voyage to America, the Mayflower's passengers faced cramped quarters, rough seas, limited food and numbing cold.

For all its prominence and power in the mid-19th century, the Whig party became divided over slavery and couldn't keep it together.

For starters, the colonists weren't protesting higher taxes on tea.

From shouting candidates' names, to punching cards to electronic scanning, the nature of voting has a long, sometimes bumpy history in the United States.

Sudden illnesses, assassinations and elections all abbreviated these presidents' terms in office.

A 1905 decision provided a powerful and controversial precedent for the flexing of government authority.

When smallpox ravaged the United States at the turn of the 20th century, many public spaces required people to show their vaccine scars for entry.

While some of the earliest pandemics faded by wiping out parts of the population, medical and public health initiatives were able to halt the spread of other diseases.

When a historic fire roared over more than 3 million acres in Montana, Idaho and Washington, the US Forest Service called for suppressing all fires. 

Doctors first tried injecting patients with blood plasma in the early 1900s. The method has been used against diphtheria, the 1918 flu pandemic, measles and Ebola.

France may be famous for its culinary legacy, but the first restaurants appeared some 600 years earlier on the other side of the world.

Roosevelt's heroism at the Battle of San Juan Hill was the culmination of years of conscious personal transformation and myth-making.

The attacks of 9/11 shocked the nation—and led to changes that altered U.S. government, travel and culture.

On September 11, 2001, 125 people inside the Pentagon were killed. The losses were devastating, but it could have been even worse.

From national parks, to clean meat to football, the 26th president left his mark on the American landscape.

Columbus's famed voyage to the New World was celebrated by Italian-Americans, in particular, as a pathway to their own acceptance in America.

The introduction of bronze led humans to develop array of new, intimidating weaponry.

The Constitution doesn't specify how many justices should serve on the Court—in fact, that number fluctuated until 1869.

The 'Father of the Nation' stressed education among his family's younger generations and even offered advice on navigating love.

The famed physicist would later denounce racism, but his diaries reveal shocking reflections from when he was a young man.

Our human ancestors' big, creative brains helped them devise tools and strategies to survive harsh climates.

From accepting a case to issuing a ruling, this is the process the nine Supreme Court justices follow in considering a case and reaching a decision.

Allied military leaders knew that casualties could be staggeringly high. Historians are still calculating the toll.