The Earth's mountains, rivers, animals and rocks have been around for millions or billions of years. Do you know which ones have been around the longest?

National Park and Earth Week are right around the corner — see how much you know about our nation's protected areas.

Whether you're crying tears of joy or crying over spilled milk, how much do you really know about the tears rolling down your face?

Lightning is more than just a stunning spectacle. Take our quiz to see how much you really know about this electrifying natural wonder.

Think you know everything about that special day of scary movies and sugar highs? Test your Halloween smarts ... if you dare.

You use pasta in sauce, in soups and in salads. But do you know the names of the different pasta types?

When the going gets tough, some animals get going — to bed. Take our hibernation quiz to see how much you know.

Every two years, the National Science Foundation asks 10 questions to see how much Americans know about science.

When it comes to decisions on electricity and energy policy, women do not have the facts they need.

Authentic sounds of the wild can now be downloaded for free to your iPhone. Assign your friends their own unique howl, hoot or roar.

Intel's Compute Stick turns your big TV into a working Windows computer.

Even though native bees don't produce honey, they're incredibly important, says author Paige Embry. She explains how to help them in "Our Native Bees."

Famed naturalist and conservationist John Muir was so much more than the father of our national parks.

There are lots of causes for sleepless nights, but it helps to know if it's insomnia or not. Thankfully, there are natural ways to get back on track.

What is Lyme disease? Here's where you are more likely to get it and the symptoms to look for if you're concerned.

In honor of Cesar Chavez Day, here are 10 interesting facts about the civil rights activist.

From their vanilla-scented secretions to their amazing ability to alter an ecosystem, here's what you need to know about beavers.

Reality can never be perfectly simulated if you take into consideration quantum complexity.

Test your knowledge of where products come from and find out if you're a savvy consumer by taking this Made in the USA quiz.

Forthcoming documentary follows movement to link poor growers with roasters and consumers.

Water leaks, especially those from plumbing pipes and fixtures, don't go away. They only get worse.

A new study finds dogs rush in — but stay calm — when they hear their human crying.

After nearly 100 years, snowballs are legal in this town again thanks to one brave kid.

The flu vaccine is your best weapon against the flu this year.

Health officials have identified a 'very strong culprit' for the devastating sickness linked to e-cigarettes.

Colorado and Washington state have legalized marijuana, and others are considering measures. Test your cannabis knowledge.

They might just kill a few sites that you know and love.

A new U.S. report on climate change offers 'information that every human needs.'

Program offers national recognition for kids working to make their world a greener place.

The EPA has unveiled a plan to limit carbon emissions from new coal-fired power plants. Here's a look at what the rules could mean.

The Environmental Protection Agency spent MLK Day spreading the gospel of food waste reduction to faith-based groups.

BrightFarms cuts out the middle man and grows local produce at the store.

Father-daughter team turns a common race practice into a clever opportunity to help the less fortunate.

The bat-killing fungal infection known as white-nose syndrome has been found in two new U.S. states.

A once-'mild' virus found in Africa 70 years ago is now running wild. Here's everything you need to know.

Feral cats cover a staggering 99.8 percent of Australian landmass, according to a new report in the journal Biological Conservation.

NASA aims to launch a flight test Thursday, June 4, of an innovative "flying saucer" that could help humans land on Mars in the future.

The European Space Agency's ExoMars mission is a two-phase operation that will look for methane, ice and landing sites for future rovers.

Finding water ice could change everything we thought we knew about the red planet, and make colonization feasible.

NASA's open source plans for a smaller model of the Mars Curiosity rover are meant to inspire next-gen STEM students.

The backwoods genius of 'Billy Bob's Gags to Riches' lives high off low-brow novelties.

New Hampshire distillery Tamworth turns the healthy spice into a tribute to Alexander Von Humboldt, the "forgotten father of environmentalism."

Palm oil's effect on the environment and the people directly and indirectly involved with its creation is detrimental. Here are some of the issues.

The new U.S. plan to limit power plant emissions is 645 pages long. Here's what you need to know.

The new U.N. climate agreement is being called 'a monumental triumph' and 'a turning point for the world.' Here are a few key points to keep in mind.

Facebook knows who your romantic partner is, even if you keep that information private, and can even predict if the relationship will last.

World Wildlife Fund, the Red Cross and UNICEF are among the first users of the new "Donate Now" button.

The idea grew out of disaster message boards that sprung up on Facebook after Japan's most recent natural disaster.

New research shows that just clicking the 'like' button reveals more about us than we realize.

If you see this tagline on your teen's social media pages, here's what's going on.