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.

“Are you here for the Winery Tour?” This is a Western Grey Kangaroo caught lounging in the wineries of the Adelaide Hills in South Australia. This past Autumn has been a spectacular time for wildlife viewing and I got lucky to spot this guy while mountain biking in the hills. Such a funny stance it just begs the question... Have you been drinking? ...and or... Are you here for the Winery Tour? Such a spontaneous moment I figured it would be perfect for an entry. I hope you like it! Cheers. Photo location: Adelaide Hills, South Australia, Australia. (Photo and caption by Greg Snell/National Geographic Photo Contest)

“Der Jen (Dezhen; 德珍繪館) has achieved fame in her homeland and that fame is now spreading to other parts of the world as more and more people become familiar with her beautiful paintings. This Taiwanese artist depicts these beautiful ladies in classic, traditional dress that would have been worn by members of the royal court or an empress herself. Traditional hair styles and jewelry depicted in her pieces are also considered authentic. Der Jens art can be found in Chinese advertising, childrens magazines, romance novels, tarot cards, and even on public transit tickets. Its also making its way to our pcs as desktop wallpaper”.

Photo: Der Jen (Dezhen; 德珍繪館) – “The beauty of Brocade” (please click to enlarge).

“Inspired by the French authorities' solution to move Romas from point A to point B, Romanian authorities planned and started forced evictions of Roma informal settlements in cities like Cluj-Napoca and Baia Mare. Some of these settlements date back to the early 1990’s. These communities were tolerated by the authorities who verbally encouraged Romas to build in the area, meanwhile, reassuring them nothing bad would ever happen to them. However, the the reality today is that during political campaigns, authorities are planning forced evictions without reasons other than ethnic cleansing of the cities. My home documents the every day life of Roma communities in Romania, 2011”. – Mugur Varzariu. (Photo by Mugur Varzariu, 2011 FotoVisura Grant Finalist)

“NASA's Pathfinder, Pathfinder Plus, Centurion and Helios Prototype were an evolutionary series of solar- and fuel-cell-system-powered unmanned aerial vehicles. AeroVironment, Inc. developed the vehicles under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. They were built to develop the technologies that would allow long-term, high-altitude aircraft to serve as “atmospheric satellites”, to perform atmospheric research tasks as well as serve as communications platforms”. – Wikipedia

Photo: The solar-electric Helios Prototype flying wing is flies over the Hawaiian islands of Niihau and Lehua during the first solar-powered test flight July 14, 2001 from the U.S. Navy's Pacific Missile Range Facility on Kauai, HI. The 18-hour flight was a functional checkout of the aircraft's systems and performance in preparation for an attempt to reach sustained flight at 100,000 feet altitude later in the summer. (Photo Courtesy of NASA/Getty Images)

“The Dream Chaser is a planned crewed suborbital and orbital vertical-takeoff, horizontal-landing (VTHL) lifting-body spaceplane being developed by SpaceDev, a wholly owned subsidiary of Sierra Nevada Corporation (SNC). The Dream Chaser design is planned to carry seven people to and from low earth orbit. The vehicle would launch vertically on an Atlas V and land horizontally on conventional runways”. – Wikipedia

Photo: NASA Deputy Administrator Lori Garver talks during a press conference with Sierra Nevada's Dream Chaser spacecraft in the background at the University of Colorado at Boulder on February 5, 2011 in Boulder, Colorado. Sierra Nevada's Dream Chaser spacecraft is under development with support from NASA's Commercial Crew Development Program to provide crew transportation to and from low Earth orbit. NASA is helping private companies develop innovative technologies to ensure that the U.S. remains competitive in future space endeavors. (Photo by Bill Ingalls/NASA via Getty Images)

Participants take part in the world's first “Pokemon Go” competition in Hong Kong, China, August 6, 2016. The competition began around 2 in the afternoon local time when organizers began announcing the rules on their Facebook page. Contestants had to take screenshots of 12 specific Pokémon in three different districts. Apart from the 12 key Pokémon, participants could also catch designated rare Pokemons which would take off some minutes from their total time. The winner was 21 year old Frankie Chu. The champ took home roughly three hundred and eighty six dollars that he says he will use to pay his school fees. (Photo by Tyrone Siu/Reuters)

A robot named “Robovie-II”, developed by Japanese robotics research institution ATR, moves around at a grocery store during a shopping assisting experiment by utilizing the robot in an ubiquitous network technology platform in Kyoto, western Japan January 6, 2010. (Photo by Yuriko Nakao/Reuters)