Great Wall of China seen from satellite (Photo credit: Wikipedia) Like the Great Pyramids of Giza, the Great Wall of China is an instantly recognizable landmark. In fact under perfect visual conditions and at a distance of 160 kilometers from the Earth the Great Wall is visible from low orbit. However not everyone knows how such a massive structure came into being. Who built the Great Wall of China? When?

The first bridges used by humans weren’t even man-made – they were as simple as a log falling over the river in a certain way, or a bunch of rocks that allowed safe crossing of a river. Bridges have always been a human necessity, and prove a unique challenge to whoever is building them. No two bridges will sit on the exact same space of land, and as such each bridge design is completely unique and built to meet its own set of engineering challenges.

Space remains one of the few frontiers left for humanity to explore – and what a vast frontier it is. Yet despite the enormity of the challenge, we’re making progress everyday – with the recent Curiosity landing on Mars, and even a planned human expedition to the Red Planet in the works for 2018. With such a vast expanse of stars and planets, constantly expanding, changing, a common question we get from those attempting to grasp the vast magnitude of space is “what’s the biggest star in the universe?

The Clothes Moth and Your Ugly Christmas Sweater Have you ever scrounged through your drawers to find that one ugly wool sweater you got last Christmas, only to find it had been mercifully torn apart by moths? Tineola bisselliella, the clothes moth, can cause extreme damage to fabrics, furniture, books and fur. Most people know that moths can destroy clothes, but they are not just eating through the cloth to get to something else.

When the first few gray hairs pop up, they often cause full blown panic. Gray hair usually represents the first trumpets that herald the aging process. A study published in 2012 reported that the average onset of graying occurs at age 40. The study also showed that the pattern of gray depends on your gender, your smoking habits and the age at which graying began. The average onset may be 40, but some people go gray as early as puberty.

Mars is the 2nd smallest planet in the solar system next to Mercury. It’s also the 4th planet from the sun, and the second closest planet to Earth. Mars is approximately half the size of Earth (which is the solar system’s 4th smallest planet) in terms of diameter, 53% to be exact. Of course, when you’re trying to answer the question “how big is mars”, there are a number of ways to arrive at an answer, depending on the measurements you want to look at.

Young Lovers Kissing (Photo credit: Wikipedia) Her emerald green eyes stare into yours as you slip your arm around her waist and pull her in. Your lips approach as if drawn in by an invisible force. As your faces draw close, your heads tilt to the right so your noses and foreheads don’t clunk together, even while your eyes are closing at the same time. At that moment, your lips touch for the first time, and an electric feeling courses through your whole body.

Chicken and Rooster (Photo credit: Wikipedia) “Which came first the chicken or the egg?” is one of the most famous riddles of all time. Its a popular riddle because its such a simple question, yet so baffling. The recent discovery of a rare fossilized dinosaur nest may share some light on this question, according to Francois Therrien, the curator of dinosaur paleoecology at the Royal Tyrrell Museum in Drumheller, Alberta, Canada.

Yogurt With Fruit (Photo credit: Wikipedia) Yes, yogurt is absolutely good for you! Despite the hype around “giving up dairy”, the truth is that the right yogurt is extremely good for you and you shouldn’t leave it out of your diet. There are many health benefits from reduction of your risk of certain types of colon cancer, to a stronger immune system and much more. And besides, it tastes great!

Water (Photo credit: Wikipedia) Water is the fundamental building block of all known life forms. There are organisms that can survive indefinitely without oxygen, in boiling temperatures, in near absolute zero freezing environments, even in the radioactive vacuum of space - but absolutely nothing can live without water. With our bodies being 65% water, humans are especially vulnerable to dehydration. We constantly lose water through sweat, urine, feces, and even in our breath.