References

A buildup of dental plaque breaks down tooth enamel, leading to tooth decay, gum disease and other oral health conditions.

Having a stuffy nose often comes with pain and tenderness around your cheeks, eyes or forehead. But what do blocked sinuses look like inside your head?

Coming down with a cold or the flu can muffle your hearing, but why?

Heart murmurs are extra, unusual sounds heard during a heartbeat — but why do they happen?

After you've eaten beets, your poop and urine can take on a shocking red or pink color — but why?

The speed at which food moves through the digestive tract depends on many factors.

The prehistoric monument Stonehenge was built up to 5,000 years ago on Salisbury Plain in England, but its ultimate purpose remains a tantalizing mystery.

Several muscles could be called the "largest" in the body, depending on whether you're talking mass or surface area, but the body's smallest muscle has no competition.

Reference The four fundamental states of matter are solid, liquid, gas and plasma, but there others, such as Bose-Einstein condensates and time crystals, that are man-made.

Freckles can reappear or become darker after sun exposure and then fade in less-sunny seasons.

It's normal for you to occasionally get dizzy and for your vision to go dark when you stand up, but it can sometimes be a sign of a chronic health condition.

Improving our "stewardship" of antibiotics is key to preventing bacteria from gaining resistance to the essential drugs.

Stress can cause "nervous stomach," but what is the link between negative emotions and uncomfortable digestive symptoms?

From stress to dehydration, there are many reasons why some people's veins may be "hard to find" when they're getting an infusion or blood draw.

Whether it's from a day at the beach or a trip to the swimming pool, getting water stuck in your ear is very common. But how does it happen?

Pareidolia is the phenomenon in which people see faces or other patterns in ambiguous images, such as Jesus on toast or the man in the moon.

We currently know of 5,502 planets beyond the solar system, but we've only found the tiniest fraction of the planets astronomers think lie elsewhere in the universe.

Surviving a fall from a great height is medically improbable, but not impossible. How do some people survive?

Neon green, ultraviolet, rainbows — the variety of colors animals can make seem endless.

Cities like Lahore, Pakistan, Hotan China and Delhi, India have consistently poor air quality, but it's impossible to accurately identify the city with the world's worst air pollution.