Spanish flu: The deadliest pandemic in history By All About History Over 100 years ago, a killer strain of the influenza virus infected over a third of the world's population.
Lindisfarne: The 'Holy Island' where Vikings spilled the 'blood of saints' By Owen Jarus Reference article: Facts about Lindisfarne.
What is climate change, and how is it affecting Earth? By Stephanie Pappas Climate change is real and humans are causing it.
How does hand sanitizer work? By Kimberly Hickok Here's why you need at least 60% alcohol in your hand sanitizer.
What is lactic acid? (And where does it come from?) By Isobel Whitcomb Is lactate really "the bad boy of exercise?"
The Gregorian calendar: Why we have Leap years and April Fools' Day By Robert Coolman The Gregorian calendar — used by most of the world — was introduced to fix errors in the Julian calendar mostly having to do with leap years.
Schrödinger's cat: The favorite, misunderstood pet of quantum mechanics By Adam Mann To meow or not to meow?
What was the Manhattan Project? By Isobel Whitcomb Hundreds of thousands of Americans participated in the Manhattan Project. Most of them had no idea.
Legionnaires' disease: Causes, symptoms and treatment By Cari Nierenberg Reference article: Facts about Legionnaires' disease.
Raising the flag on Iwo Jima: Here's the story behind that iconic World War II photo By All About History, Tom Garner On Feb. 23, 1945, six Marines raised the U.S. flag over the Japanese island of Iwo Jima. Their photo is one of the most iconic images of World War II.
Hemophilia: Causes, symptoms & treatment By Cari Nierenberg One of the main risks of this rare blood disorder is internal bleeding into muscles, joints and soft tissue.
Prostate cancer: Causes, symptoms & treatment By Kimberly Hickok Prostate cancer is the second most common form of cancer in men.
What is global warming? By Stephanie Pappas Global warming is the gradual heating of Earth's surface, oceans and atmosphere.
The Battle of Iwo Jima: A gruesome victory for the Allied Forces By All About History, Tom Garner Fought on a tiny volcanic island 75 years ago, this brutal clash between American and Japanese forces defined the horror of the Pacific theater.
What is a coronavirus? By Nicoletta Lanese SARS, MERS and the common cold are all types of coronaviruses.
Megalodon: Facts about the long-gone, giant shark By Alina Bradford Megalodon was the largest shark and one of the largest fish on record. It went extinct about 2.6 million years ago.
Why is Jerusalem important? A Q&A with historian and author Simon Sebag Montefiore By All About History Jerusalem is the epicenter of several of the world's major religions, but its importance is much more than just spiritual.
Anemia: Causes, symptoms and treatment By Cari Nierenberg Anemia is a common condition that may be caused by a shortage of iron, abnormal bleeding, infections, cancer or gastrointestinal problems.
What is ocean acidification? By Tim Childers The global increase in carbon dioxide emissions is not only warming our planet at an alarming rate, but it's also making our oceans more acidic.