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.

“This is the heart-stopping moment a photographer came within inches of a young cheetah when it stuck its head through her sun roof. Australian Bobby-Jo Clow, 31, was on safari in Tanzania when the juvenile started heading towards her Landrover with his sibling. She snapped away as the young male dangled its paws in front of her face and smelt her hair before its mother called it away into the wilds of the Serengeti National Park. But not until Bobby-Jo, a full-time elephant keeper at a Tanzanian Zoo, had leaned forward enough to capture the perfect shot, causing the cheetah to hiss and bare its teeth”. – Caters News. (Photo by Bobby-Jo Clow/Caters News)

An Armatix employee holds a “smart gun” by the company at the Armatix headquarters in Munich May 14, 2014. The gun is implanted with an electronic chip that allows it to be fired only if the shooter is wearing a watch that communicates with it through a radio signal. If the gun is moved more than 10 inches (25 cm) from the watch, it will not fire. A Maryland gun shop owner has dropped his plan to be the first in the United States to sell the so-called “smart gun” after a backlash that included death threats. (Photo by Michael Dalder/Reuters)

Belgian riot police officers are covered by hay and eggs thrown by demonstrators as farmers and dairy farmers from all over Europe take part in a demonstration outside an European Union farm ministers emergency meeting at the EU Council headquarters in Brussels, Belgium, September 7, 2015. Thousands of farmers gathered in the European capital calling for more help with low prices and high costs. (Photo by Jacky Naegelen/Reuters)

Firefighters watch as an air tanker drops retardant while battling the Ferguson fire in the Stanislaus National Forest, near Yosemite National Park, California on July 21, 2018. A fire that claimed the life of one firefighter and injured two others near California's Yosemite national park has almost doubled in size in three days, authorities said Friday. (Photo by Noah Berger/AFP Photo)

Photographer Pol Kurucz’s vivid collection of photos explores issues faced by black Brazilian women, from political misrepresentation to unrealistic beauty standards. Kolor Collective is a Rio de Janeiro-based creative group that challenges the struggle faced by black women in Brazil through theatrical and provocative art. It was founded in 2015 by Franco-Hungarian photographer Pol Kurucz, who often touches on his own experiences of discrimination to call out sensitive social problems. (Photo by Kolor Art Collective/The Guardian)

When Dutch photographer Marcel Heijnen moved to Hong Kong, the territory’s shop cats instantly caught his eye. While the “feline emperors” are the stars, his shots also offer insights into Hong Kong’s wares, from dried fish to paper. Here: Hong Kong Shop Cats #17. (Photo by Marcel Heijnen/Blue Lotus)

“Dubai is sometimes called the “City of Gold” because of its stunning growth from a sleepy Gulf port to a world-famous business crossroads in the space of a single generation. Its nickname has a literal meaning for traders in the precious metal. The city is building itself up as a center for the gold trade, between sources in Africa and consumers in the rising economies of China and India”. – Kamran Jebreili via Associated Press

Photo: A gold press operator collects 10 gram gold blanks to press them with the logo of the Emirates Gold company in Dubai, United Arab Emirates. Gold prices remained relatively steady in 2012, close to $1,700 an ounce. (Photo by Kamran Jebreili/AP Photo)