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.
Flu Shot Facts & Side Effects By Rachael Rettner The seasonal flu shot is a yearly vaccine administered to protect against the flu, or influenza. In the United States, flu shots are recommended for everyone ages 6 months and older.
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.
Psilocybin: The magic ingredient in psychedelic shrooms By Cari Nierenberg Psilocybin, like other psychedelics, is illegal, but controlled doses may have therapeutic effects.
What is toxoplasmosis? By Nicoletta Lanese This parasitic infection hijacks rodent brains and infects people through dirty cat litter. There's a good chance you have it.
Neuroblastoma: Causes, symptoms & treatment By Cari Nierenberg Neuroblastoma is a rare form of childhood cancer that occurs when early forms of nerve cells don't develop correctly.
What is collagen? By Rachel Ross Your body might fall apart were it not for collagen. Good thing a healthy body naturally produces all the collagen it needs.
What is the amygdala? By Nicole Haloupek The amygdala is often referred to as the "fear center" of the brain — but this name hardly does justice to the amygdala's complexity.
