The Civil War turned the Continental Divide into an American symbol of identity

US westward expansion—and the status of slavery in the new territories—was a major cause of the American Civil War

The addition of new western lands forced the nation to confront whether slavery would spread beyond the South. Each debate over the admission of a new state sharpened the divide between free and slaveholding regions.

Hear how the world reacted to the American Civil War

European nations closely watched the Civil War for its economic and political consequences. Some European nations quietly engaged diplomatically with the Confederacy but withheld recognition. When the Union made slavery's abolition a central cause, European public opinion turned sharply against the South.

37 maps that explain the American Civil War

This collection of 37 maps tells the story of the American Civil War as well as any historical account. See how and where the war began and why, and where the major battles were fought. Discover how the North achieved victory and the many ways the war changed America forever.

The Civil War introduced many technological advances to both society and warfare

The conflict accelerated innovations—including railroads, telegraphs, ironclad ships, and mass-produced weapons—while advances in photography, medicine, and manufacturing transformed how Americans communicated, healed, and built after the war.

The Civil War permanently strengthened federal power

The Civil War expanded federal power through emancipation, national military mobilization, and postwar civil rights laws, permanently strengthening the national government and shifting the balance of authority away from the states.

The devastation of the American Civil War led to the establishment of Memorial Day

Tracing its origins to the post-Civil War era, Memorial Day began as local tributes to those who lost their lives in the war. Originally taking place annually on May 30, it was moved to the final Monday in May in 1971.

The Confederate flag that most people recognize was not the national flag

The familiar Confederate flag was actually a battlefield banner; the Confederacy's true national flag, the "Stars and Bars," featured a blue canton with white stars and red-white-red stripes resembling the US flag.

Emanuel Leutze's painting 'Washington Crossing the Delaware' is one of the defining images of the Revolutionary War

The scene depicts George Washington leading Continental forces across the icy Delaware River on Christmas Day, 1776, enabling a surprise attack on British-paid mercenary troops at Trenton. This risky maneuver revived the revolution after months of defeat.

The Union victory at Gettysburg marked a major turning point in the war

Fought July 1-3, 1863, the Battle of Gettysburg ended the Confederate invasion of the North. While the Union lost nearly 23,000 troops, its victory in one of America's most famous battles shifted the war's momentum decisively toward the North.

Early American citizenship was defined inconsistently by individual states

The original US Constitution did not define national citizenship, leaving it to the states to apply their own rules. This led to inconsistent and often exclusionary standards across the country until after the Civil War.

The Appalachian Mountains blocked east–west boat travel until the Erie Canal

The Appalachian Mountains, spanning from Alabama to Canada, long hindered inland commerce. The Erie Canal created the first reliable water route through the range by leveraging the natural valley of the Mohawk River, revolutionizing trade and migration.

The American Revolution became a template for a colonized world

The robust and radical transformation during the American Revolution created a template for dozens of future independence movements. Its key ideas of republicanism, individualism, and equality inspired revolutions in France, Haiti, Ireland, and more, paving the way for the broadly democratic world we know today.

The wall separating East and West Berlin was a highly visible symbol of the Cold War

Built in 1961, the Berlin Wall physically separated East and West Berlin for nearly three decades—preventing East Germans from fleeing to the West. Its fall in 1989 signaled the collapse of communist regimes across Eastern Europe.

Grant's third-term ambitions helped create the GOP's elephant symbol

In 1874, as Republicans debated Ulysses S. Grant possibly seeking a third term, Harper's Weekly ran a Thomas Nast cartoon showing a panicked elephant labeled "The Republican Vote." The image caught on, cementing the elephant as the GOP's enduring symbol.

The portrait of George Washington was first placed on the one-dollar bill in 1869

Trace the history of the US dollar from its colonial roots to its adoption as the national currency. The video explores the word's Germanic origins, how the dollar sign evolved from the Spanish peso, and how Washington's portrait came to define US paper currency.

Coastal vacation destinations were developed with railroad companies

The American vacation developed as the country expanded its railroad infrastructure in the late 1800s, with businessmen positioning coastal enclaves like Coney Island and Atlantic City as affordable respites from the country’s urban centers.

American Express stopped its rail service when President Wilson seized American railroads

After the US entered World War I, the federal government took control of American railways and consolidated rail companies. American Express officially exited the express shipping business in 1918 and turned its focus to its travel and financial services.

At the 1787 Constitutional Convention, Madison changed the draft language from Congress's power to "make" war to "declare" war

The change was deliberate: "make" war seemed to leave the president unable to defend the country against sudden attack, while "declare" preserved that defensive authority. The distinction between starting a war and responding to one has been debated ever since.

The disputed 1876 Presidential election accelerated the end of Reconstruction

The 1876 election between Rutherford B. Hayes and Samuel J. Tilden ended in a deadlock over contested Southern votes. To resolve the crisis, Democrats accepted Hayes's presidency in exchange for the withdrawal of federal troops—formally ending Reconstruction.

Many myths continue to circulate about the first Thanksgiving

The Thanksgiving myth didn’t really start in 1621, argues historian David Silverman in this interview with Smithsonian. Rather, it took hold over 200 years later. During the Civil War, Thanksgiving was declared a national holiday by Abraham Lincoln as a way to promote national unity. The tidy story of friendship between Native Americans and colonists was used to quell racial tensions of the late 19th century.

Many consider Twain 'the father of American literature'

In "Green Hills of Africa," Ernest Hemingway declared that all modern American literature sprang from Twain's "Adventures of Huckleberry Finn." That's a sentiment shared by many scholars, who assert that Twain's book changed American fiction by challenging the country's racist history and incorporating a more realistic vernacular.

The Bill of Rights toured the United States on the Freedom Train from 1947 to 1949

Alongside the Declaration of Independence and the Constitution, the Bill of Rights traveled the country for 18 months. Nearly 3.5 million people viewed the documents as they traveled to all 48 contiguous states in the US. (Alaska and Hawaii were not yet states.)

Explore an interactive map of battles from the American Revolution, along with detailed summaries of each engagement

The US finished what the French had started with Panama's canal

For about two decades, Suez Canal-builder and Frenchman Ferdinand de Lesseps led the project, but financial troubles forced it into the hands of the US, who completed it in 1914. This timeline, made to accompany the definitive PBS American Experience documentary about the canal, highlights major moments in its construction.

Explore the social and cultural history of the Mexican-American War

Historian Peter Guardino joins host Don Wildman to explore how the war shaped ordinary lives on both sides of the border. Drawing from The Dead March, the episode reveals how culture, class, and ideology shaped the conflict and its consequences.

Railroads and long-distance communication led to the development of time zones

Noon had been determined independently at each location based on when the sun was highest in the sky, but this became impractical for standardizing transportation. British star-mapping and navigation advancements established Greenwich as the prime meridian through Greenwich Mean Time, or GMT.

The rivalry between Alexander Hamilton and Thomas Jefferson centered on federalism—the question of how much power the federal government should hold relative to the states.

The original copy of the Declaration of Independence is not a pristine document, and even features a smudged anonymous handprint in the bottom left corner.

'Grand Canyon of the Yellowstone,' a work by American painter Thomas Moran, inspired Congress to establish Yellowstone National Park.

Abraham Lincoln was almost assassinated weeks before his inauguration as he traveled from Illinois to DC through Baltimore in 1861; it took two independent claims for Lincoln to be convinced the threat was real

The US Constitution is widely regarded as the longest-standing written national constitution still in force—see how it has influenced rights worldwide.

The American Society of Civil Engineers' infrastructure report card gave the US a C in 2025, its highest grade since the project launched in 1998.

Many legends about George Washington, including his supposed wooden teeth and the story of cutting down the cherry tree, lack evidence.

See the most iconic photos from four decades of LIFE magazine

Hear about the 250-year history of the United States Postal Service, complete with some of its strangest deliveries, important innovations, and the figures that made it an American institution.

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.

The United States has had a tumultuous relationship with Cuba since its 1959 revolution, highlighted by a nuclear crisis and a decades-long trade embargo.

The concept of phantom limbs, the perception that amputated limbs are still present, dates back to a French military surgeon in the 16th century.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

Some coin denominations have ridges etched on their sides, partly to prevent counterfeiting, in a practice called 'reeding.'

Hurricanes, which rely on air consistently spinning in the same direction, cannot cross the equator because air curves in opposite directions north and south of it.

The name 'Silicon Valley' arose from the founding of Shockley Semiconductor Laboratory in Fairchild Semiconductor in 1956-57, founded near Stanford University in Palo Alto

The Russia-Ukraine conflict is the largest ground war in Europe since World War II in terms of casualties, forces mobilized, and displacement of civilians.

A small portion of The Winstons' 'Amen, Brother,' an obscure '60s gospel record, is the basis for thousands of hip-hop tracks, making it one of the most sampled records ever that's informally known as 'the Amen break.'

Dozens of S&P 500 stocks, including Coca-Cola and Walmart—known as the dividend aristocrats—have increased dividends every year for 25 years

See how Budweiser's famous Clydesdales spend their days at Warm Springs Ranch, where roughly 70 to 80 of the beer brand's giant horses can be found at any given time.

Power lines are dotted with large, brightly colored balls to improve the visibility of these thin wires to helicopters and small planes and help prevent potential crashes.

Walt Disney's early film 'Alice's Wonderland' was a groundbreaking innovation in the silent film era

Sunflowers have long been a symbol of nuclear disarmament because they can extract large amounts of radioactive cesium from soil.

Ebola species have historically been named after where they were discovered, stigmatizing residents who live there, including Bundibugyo, in Uganda.