Venezuelan migrant and rap singer, Alfonso Mendoza aka “Alca”, 25, practice with his skateboard in a park in Barranquilla, Colombia on September 28, 2018. Alca -who arrived in Colombia nine months ago due to the crisis in his country- was born without legs and changed the wheelchair for a skateboard. At present, he is an example of overcoming adversity, practicing extreme sports, singing rap and giving conferences to young people in vulnerable situations. (Photo by Raul Arboleda/AFP Photo)

“The scientists behind NASA's $2.5 billion Curiosity rover mission on Mars on Tuesday explained the nature of a tiny, gleaming "flower" embedded in Red Planet rock, and revealed where they'll be using the SUV-sized robot's drill for the first time”. – Alan Boyle via NBCNews.com

Photo: Scientists say that a “Martian flower”, seen here in an image from the Curiosity rover's Mars Hand Lens Imager, is a 2-millimeter-wide grain or pebble that's embedded in the surrounding rock. Another, darker-colored mineral grain can be seen above and to the left. (Photo by NASA)

If we were to burn NH4Cr2O7 with HgSCN in the Dark Ages in Europe and show it to anyone, it is us who would be burning next on a fiery cross of Inquisition. And it’s no wonder, since this experiment produces a truly marvelous result. At first, as you ignite the mixture of NH4Cr2O7 and HgSCN, all you can see is that it is slowly burning with a reddish flame. After a while, however, a crater is formed in the middle of the burning pile, and then, suddenly, tentacle-like appendages start sprouting from the burning mixture. And you can almost hear the scream of the mad occultist – “Come forth, Kraken! Come forth!” But of course, this is simply a chemical reaction that is called the "Pharoah's Serpent". It was also often sold in firework stores until people realized that it was toxic.

Ricardo Azevedo rides his Honda NX 200 motorbike, which he converted to be powered by water, in Salto, northwest of Sao Paulo, Brazil, August 6, 2015. The Sao Paulo civil servant built the motorbike, which can cover up to 500 kilometres (311 miles) fuelled by just one litre of water. Dubbed “Moto Power H2O” the bike is powered by the process of electrolysis, which breaks the water molecule down into its constituent elements. (Photo by Nacho Doce/Reuters)

A Vietnamese artist acting as a medium, performs the “Hau Dong” ritual at Viet Theatre in Hanoi January 16, 2016. For the first time, Vietnamese drama director Viet Tu has brought the ritual from religious temples to the theatre partly to draw tourists. The “Hau Dong” is a ritual where a medium puts on special costumes and tells stories of gods and heroes while being accompanied by “Chau Van” music, as part of the act of Dao Mau – the worship of mother goddesses in Vietnam. It is believed that the medium is capable of having a direct contact with spirits during the ritual. (Photo by Reuters/Kham)

Projectionist Antonio Feliciano, 75, checks his projector before showing a film in Monforte, Portugal May 16, 2015. Shades of Oscar-winning classic "Cinema Paradiso" run through the life of Feliciano, a sprightly 75-year-old who fears he may be the last of Portugal's travelling film projectionists.After six decades travelling four million km (2.5 million miles) to screen 4,000 films in Portugal's far-flung villages, Feliciano does not plan to retire just yet. But he is resigned to the fact that the Internet, digital TV and distribution monopolies have made his craft obsolete. (Photo by Rafael Marchante/Reuters)

“Eyes Wide Open is an exhibit created by the American Friends Service Committee observing the American soldiers and marines that have died in the Iraq War. It contains a pair of combat boots to represent every American soldier and marine that has died in the war, as well as shoes representing Iraqi civilians who have lost their lives during the invasion and occupation”. – Wikipedia

Photo: A man pauses as he looks at rows of combat boots that are part of the "Eyes Wide Open" exhibit in front of San Francisco City Hall on March 19, 2012 in San Francisco, California. The Eyes Wide Open exhibition includes a pair of boots for every one of the 481 California servicemen and women who died in the Iraq war. (Photo by Justin Sullivan/Getty Images)

Some foods have significantly more Calories than others but what does the difference actually look like. Each of the photographs below represents 200 Calories of the particular type of food; the images are sorted from low to high calorie density. When you consider that an entire plate of broccoli contains the same number of Calories as a small spoonful of peanut butter, you might think twice the next time you decide what to eat. According to the U.S. Department of Agriculture, the average adult needs to consume about 2000 - 2500 Calories to maintain their weight. In other words, you have a fixed amount of Calories to "spend" each day; based on the following pictures, which would you eat?