Dave Roos

From a magnet that can lift an aircraft carrier to a turbine blade longer than a football field, these brawny behemoths get the big jobs done.

Did humans first set foot in the Americas after walking—or sailing or paddling by sea?

These dietary staples were cultivated over thousands of years by Indigenous peoples of America.

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

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

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

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

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.

Evidence of powerful earthquakes linked to the Vesuvius eruption adds to the story about why so many people perished at Pompeii in 79 A.D.

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.

Black Friday hasn't always been about shopping for sales at obscenely early hours the day after Thanksgiving.

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

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

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

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.

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

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

In Plato's 'Republic,' the ancient Greek philosopher lays out five different forms of government, ranging from ideal to oppressive.

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

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

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

Wright designed the iconic home perched over a waterfall in 1934 as a full realization of what he called "organic architecture."

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.

The 13th-century pact inspired the U.S. Founding Fathers as they wrote the documents that would shape the nation.

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.

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

A brash, self-made millionaire helped fund the fight for independence, but after the war, he ended up in debtor's prison.

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.

From a son of Benjamin Franklin to a Mohawk leader to the governor of Massachusetts, these men chose to side with the British.

An estimated 30,000 Hessian troops were tapped by rulers in German territories. Some welcomed the journey abroad; others were forced to join the fight.

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.

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

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

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.

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

The once-great empire on the Nile was slowly brought to its knees by a centuries-long drought, economic crises and opportunistic foreign invaders.

From axes to swords to chariots, see the weapons that helped make ancient Egyptian warriors formidable.

A dagger crafted from meteorite and the remains of King Tut's stillborn daughters are among the stunning artifacts found in the tomb.

In Athens and Rome, voting could entail shouting contests, secret stone ballots and an election system with built-in bias for the wealthy.

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

These eight objects played a role in the daily lives of people living in the cradle of Western civilization nearly 3,000 years ago.

In addition to slicing out the hearts of victims and spilling their blood on temple altars, the Aztecs likely also practiced a form of ritual cannibalism.

Three city-states joined in a fragile, but strategic alliance to wield tremendous power as the Aztec Empire.

Jesus wasn't the only one believed to have risen from the dead. Stories of resurrection appear in ancient cultures around the world.

In 1997, 39 members of a religious sect were found dead by suicide inside a San Diego mansion. Why did they do it?

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

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.

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

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

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

It took just four years to get the mumps vaccine ready for market—but its development leaned heavily on groundwork that had been established during World War II.

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

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

"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."

Wars, oil crises and a pandemic have all played a part in driving up inflation over the past century in the United States.

The 1955 announcement of a new vaccine was met by jubilation. But doubts and problems soon followed.

After enduring dark times, Americans were eager for a comeback.

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

Hindsight is 20/20, but the stock market threw signals back in the summer of 1929 that trouble lay ahead.

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

What did they eat at the first Thanksgiving? Which president made Thanksgiving a federal holiday? Get Thanksgiving trivia to share around the table.

From the earliest fall feasts to the first Thanksgiving football game to the Macy's Day parade, here's the full background on how the U.S. holiday evolved to the tradition it is today.

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

Learn why we kiss under the mistletoe, the commercial origins of "Rudolph the Red-Nosed Reindeer," whether Jesus was really born on Christmas Day and more.

In medieval times, Christmas celebrations carried on for multiple raucous days and nights.

William Jackson Smart was a twice-married, twice-widowed father of 14 children.

In a harrowing ordeal, JFK helped ensure the survival of his men, taking actions that would earn him a Navy and Marine Corps Medal and a Purple Heart in World War II.

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

The framers of the Constitution intentionally made it difficult to remove a president from office.

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

Among the handful of U.S. presidential rematches, the candidate who lost the first round more often came back to win.

The history of U.S. presidential elections is filled with political conventions that were anything but predictable.

From songs to toys to cigarette packs, presidential candidates have found creative ways to reach the public.

These presidents (including one who later became very unpopular) arrived at the White House with overwhelming margins of victory.

Some presidential elections have been decided by just a few thousand votes—or even a few hundred.

Framers of the Constitution identified just three requirements. The 14th and 22nd Amendments added two more.

The 1798 Alien and Sedition Acts called for deportation of people from 'hostile' nations and made it a crime to criticize the government.

Armed with inexpensive tools, treasure-hunting hobbyists the world over have made some momentous and valuable finds.

From a buck-toothed rodent to a shark that doesn't reach puberty until age 150, find out what creatures have the make-up for exceptional longevity.

One storm left an estimated 8,000 dead in its wake, while an epic flood carried human bodies some 350 miles away.

The Allied invasion of Normandy was among the largest military operations ever staged. Learn how many fighting forces took part, why it was called D-Day, stats on its planning, execution and more.

The official declarations of war occurred during five separate military conflicts, starting in 1812 and, most recently, in 1942.

From the Civil War to the rule of Ferdinand Marcos in the Philippines, find out how martial law has been enforced—and exploited.

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

More than a dozen sitting presidents have faced Congressional censure, but the official reprimands do not carry the weight of law.

Before Marshall became chief justice in 1801, the Supreme Court operated out of a borrowed room and wielded little authority.

Humans have conceived versions of intelligent machines for centuries.

From dead rats implanted with bombs, to a giant explosive wheel, these World War II weapons were creative, but not very successful.

Lamarr was a glamorous movie star by day, but she was also a gifted, self-trained inventor who developed a technology to help sink Nazi U-boats.