The expedition produced the first detailed climate records of the West

Clark’s maps provided the first detailed record of the American West

Covering over 8,000 miles, William Clark’s maps charted rivers, mountains, and tribal territories with remarkable accuracy. Equipped with sextants, compasses, telescopes, and more, Clark became an expert at surveying—requiring extensive celestial and topographical observations each day.

Lewis and Clark’s journey became a blueprint for future exploration

Combining science, diplomacy, and logistics, the Corps of Discovery created a model for later expeditions—from charting the Arctic to NASA’s space missions.

The expedition documented 240 plant species, 178 new to western science

Lewis and Clark’s botanical records introduced species to Americans like bitterroot, ponderosa pine, and Oregon grape—plants unknown to western science at the time. See a selection of these species in this image gallery.

The Lewis and Clark expedition lasted over two years

The Corps of Discovery departed St. Louis in May 1804 and returned in September 1806, covering more than 8,000 miles by boat, horseback, and on foot. See a timeline of the journey’s key events.

Jefferson sent Lewis and Clark to map, trade, and secure the West

Beyond seeking a water route to the Pacific, Jefferson tasked the Corps of Discovery with mapping the new Louisiana Territory, cataloging its resources, and establishing trade with Native nations.

The Corps of Discovery braved wildlife, weather, and near-starvation

Along their 8,000-mile trek through territory populated by tribes suspicious of their intentions, Lewis and Clark’s party faced many dangers—including grizzly bear attacks, freezing winters, treacherous river crossings, and periods of near-starvation. Watch a 30-minute elaboration of their heroic efforts here.

Discover the 'American Serengeti' Lewis and Clark first recorded

This podcast traces the 19th-century exploration of the Great Plains’ biodiversity—beginning with Lewis and Clark’s wildlife cataloging and continuing through a century of documenting the Natural West’s remarkable species and landscapes.

A free archive of firsthand historical documents from explorers of America

Maintained by the Wisconsin Historical Society, the American Journeys collection contains more than 18,000 pages of primary source documents—journals, letters, maps, and accounts written between roughly 1000 CE and the early 1800s. These include eyewitness records of the Norse arrival in North America, Spanish conquistador expeditions, and the Lewis and Clark journey. Browse this list of highlights where pages from the original texts are specified (clicking a link opens a PDF).

The weather time machine

A fun interactive on how old ships’ logs are giving scientists new insights into the past and future of the Earth’s changing climate (w/maps and pictures).

Snowfall records from every county in the US

Discover the one-day snowfall records of every county in the US in this comprehensive map. Data from the National Oceanic and Atmospheric Administration captures inches of snowfall and the year it fell the most in each county. See the contrasts between the inches of snowfall in warm southern American states and the cooler East Coast.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

The Viking landers were the first spacecraft to conduct experiments on Mars

NASA’s Viking 1 and 2 missions tested soils for signs of life, captured images, and studied the Martian atmosphere, revealing evidence of ancient water flow, volcanic soil, and a thin carbon dioxide atmosphere.

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.

A medieval warm period reshaped agriculture across parts of the world

Between 750 and 1350 CE, some regions experienced temperatures that rivaled or exceeded late-20th-century averages, likely due to shifts in El Niño–La Niña cycles. The warmer, wetter climate in Europe and northeast North America boosted agriculture, while causing droughts elsewhere.

Why the Antarctic climate enabled British scientists to discover the ozone hole

In the Antarctic stratosphere, polar conditions facilitate the formation of polar stratospheric clouds, which allow chlorine compounds from chlorofluorocarbons to accumulate. In 1985, British Antarctic Survey scientists detected massive springtime losses over Antarctica, as accumulated compounds destroyed significant amounts of ozone once sunlight returned.

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

Favorable conditions for wildfires are becoming more frequent in the western US

A new study of the American West shows that climate change is driving more days that are hot, dry, and windy—the perfect conditions for deadly wildfires.

Explore a timeline of research from the NSF National Center for Atmospheric Research

Since its founding in 1960, the group of research institutions has pooled together observational and computational resources to make significant advancements in the atmospheric sciences. These include the discovery of coupled atmospheric systems, the development of increasingly accurate climate models, and the creation of the National Scientific Balloon Facility.

What's the difference between weather and climate?

A five-minute TedEd video exploring the differences between weather and climate – what they are, how we predict them, and what those predictions can tell us.

The 19th-century painters of the Hudson River School were among the first American romantics, with portraits that displayed the natural beauty of the young country.

Dinosaurs’ feathers and greater metabolism helped them survive polar conditions

Studies of dinosaur footprints alongside ice-deposited rock fragments indicate that early dinosaurs adapted to cold weather before the volcanic winters of the Triassic-Jurassic extinction event. These geological events helped dinosaurs to flourish by wiping out their amphibious competitors.

Madison's meticulous notes of the Constitutional Convention are the most thorough record of the event

During the Constitutional Convention, James Madison took detailed daily notes of the debates, speeches, and votes. His Notes on the Debates in the Federal Convention is the most comprehensive and authoritative account of the convention, shaping historians' understanding of the Constitution's origins.

What summer was like the year you were born

Summers have generally grown warmer, so chances are the first summer of your life was cooler than the most recent one. Stacker used official average weather data for the months of June through August from the year 1920 to 2022 in this fun data dive.

George Washington spent thousands of dollars on ice cream in a single summer

Records show that America's first president purchased a "cream machine for ice" as early as 1784. An accounting record from 1790 reveals that Washington spent $200—roughly equivalent to $6,300 today—on ice cream.

Global CO2 levels as measured at Hawaii’s Mauna Loa Observatory, managed by the US government’s NOAA.

The Global Monitoring Laboratory conducts research on greenhouse gas and carbon cycle feedbacks, changes in clouds, aerosols, and surface radiation, and recovery of stratospheric ozone.

An engineer tracked his moods for decades and helped researchers identify SAD

Civil engineer Herb Kern had bipolar and would record his moods dating back to 1967. He noticed the seasons were a major factor in the increase and severity of his episodes. By reaching out to researchers at the National Institute of Mental Health, Kern became the first human to confirm increased melatonin levels during winter and to receive bright light therapy.

Atmospheric rivers are the largest freshwater transport mechanism on Earth

Serving as highways that carry the water vapor equivalent of up to 15 times the average flow of water at the mouth of the Mississippi River, atmospheric rivers are approximately 400 to 600 kilometers (250 to 375 miles) wide and provide 30-50% of the annual precipitation of the US West Coast.

Scientists testing how climate change affects plants found, in a years-long simulation study, that poison ivy grew 70% faster with the resulting extra carbon dioxide.

The boiling temperature of water decreases with increasing elevation because the molecules need less energy to overcome the lower atmospheric pressure associated with thinner air.

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.

Chaos theory—informally known as the butterfly effect—is the reason why weather forecasts are presented with probabilities rather than certainties.

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.

Stanford built a Google Maps for the Roman Empire, revealing how much it cost to travel in the ancient world

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.

A century of Billboard issues documenting the evolution of popular music.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

Before writing 'Walden,' transcendentalist Henry David Thoreau nearly burned down his hometown with a campfire that grew out of control.

Dirty lightning is a thunderstorm created from friction between rising and falling flows of ash and smoke during volcanic eruptions.

Visualize the path of every solar eclipse from 1900 to 2099 and see what each looks like when observed from different locations on Earth.

After the Boston Tea Party, colonists switched to coffee, which became the main morning drink for revolutionaries.

See how Ebola tore through Guinea, Sierra Leone, and Liberia in 2014-2016.

The American cockroach is actually from Africa, an apparent hitchhiker aboard ships carrying enslaved people, with evidence suggesting the bug may have arrived in the New World as early as the 1600s.

Apollo astronauts left items in the moon's 'toss zone,' including golf balls, family photos, and bags of human waste, to make room for lunar rocks.

Explore the animals that populate the depths of the ocean, from fish and coral in the first few hundred feet, all the way down to the bottom of the Mariana Trench.

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.

The first horror movie is believed to be George Méliès' 1986 short 'The Haunted Castle,' which pioneered the use of special effects

While the first exchange-traded fund (a 'basket' of different assets that can be bought and sold on a stock exchange) in the US only launched in 1993, the global ETF market has grown to more than $10T in the short time since.

Elk Cloner, the first computer virus to spread in public, was written as a practical joke by Richard Skrenta, a Pittsburgh high school student.

44% of Americans say they pray at least once a day—discover how your state's religiosity stacks up against the rest of the country.