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.

Axel, a research prototype rover for exploring the Moon, Mars and other planets, is remotely driven over rocks as engineers from Jet Propulsion (JPL) and grad students from Caltech (California Institute of Technology) demonstrate its mobile over the steep and rocky grounds of the JPL Mars Yard on January 14, 2009 in Pasadena, California. The rover is capable of descending cliffs or into craters and returning by a cable tethered to its starting point. Development of the Axel rover is a point effort funded by NASA Exploration Systems Mission Directorate (ESMD) and lead by Principal Investigator Issa Newnas and Co-Investigator and Caltech professor of mechanical engineering bio engineering Joel Burdick. (Photo by David McNew/Getty Images)

This is the mesmerising image of a colourful Milky Way shining down on Mount Fuji. Steve Lance Lee, 37, captured the sky above the iconic mountain whilst on his honey moon in Lake Kawaguchiko, Japan. Mount Fuji is illuminated underneath the galaxy of stars, creating an impressive landscape. Here: The beautiful image captured by Steve Lance Lee of the Milky Way seemingly errupting from Mt. Fuji in Japan. (Photo by Steve Lance Lee/Caters News)

“Getting to see girls’ bedrooms must have been a teenage obsession for the members of the all-male photographic collective Riverboom. Now that they have more or less grown up, they have decided to transform that dream into a reality. Riverboom’s Gabriele Galimberti and Edoardo Delille are traveling the five continents to see where girls, between the ages of 18 and 30, sleep. They have discovered that girls’ bedrooms are much more then just places where they lay down their heads – they are the places where girls read, love, dream, work and play”. – Gabriele Galimberti. Photo: Katerinai, 27 – Athens, Greece. (Photo by Gabriele Galimberti/Riverboom Ltd)

“The Space Launch System, or SLS, is a Shuttle-Derived heavy launch vehicle being designed by NASA, following the cancellation of the Constellation Program, to replace the Space Shuttle after its retirement. The NASA Authorization Act of 2010 envisions the transformation of the Ares I and Ares V vehicle designs into a single launch vehicle usable for both crew and cargo. It is to be upgraded over time with more powerful versions. The proposed SLS is visually similar to the legacy Saturn V booster and in particular the proposed, two-stage, Saturn INT-20”. – Wikipedia

Photo: In this illustration provided by NASA, the design for a new space rocket system, the Space Launch System, is seen. NASA's new rocket design will reportedly cost about $35 billion and be ready to for test launch in 2017. According to NASA, the rocket will be used to carry Orion Multi-Purpose Crew Vehicle as well as cargo and science experiments to earth's orbit, as a backup for the space station and possibly destinations beyond that. (Illustration by NASA via Getty Images)

Using his camera skills, Marc meters the background sky in order to achieve the beautiful black silhouettes of the wildlife, Africa, 2010-2016. (Photo by Marc Mol/Barcroft Images)

“Banksy is an pseudonymous England based graffiti artist, political activist, film director and painter. His satirical street art and subversive epigrams combine irreverent dark humour with graffiti done in a distinctive stencilling technique. Such artistic works of political and social commentary have been featured on streets, walls, and bridges of cities throughout the world”. – Wikipedia

Photo: A Bristol Museum employee adjusts one of the latest suprise exhibits by the underground guerrilla artist, Banksy on June 12 2009 in Bristol, England. The exhibition called “Banksy versus Bristol Museum” is one of the largest single collections of the artist works and was organised under tight security and installed in just 36hrs with only a handful of museum staff aware it was even happening. Banksy, whose real identity remains a mystery, is said to hail from the Bristol area, and claims that hosting the exhibition in the city is his way of thanking the city for his early street art career. (Photo by Matt Cardy/Getty Images)

In a simpler time all a child or an adult needed to enjoy the outdoors was a ball and a stick. Or maybe an old tire tied to a high branch to fashion a swing. And the only instruction given to children was to “be home before dark”. Now there are iPads and computers and television screens and shrinking safe public spaces. But despite the distractions and limitations of space, these images show the charm of kicking a ball or skipping rope endures. Sometimes with modifications as a nod to changing times. Here: in this Saturday, June 20, 2015 photo, a boy runs while playing with a motorcycle wheel in Samugari, Ayacucho, Peru. (Photo by Rodrigo Abd/AP Photo)