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.

A group of women dance in a pool in Callao, Peru, Sunday, February 22, 2015. One of centers for the front-doorstep, pool-party phenomenon is Lima's port city of Callao. People hold parties in them and sometimes entire blocks chip in to buy a pool, which can be had in local department stores for a bit over $100. (Photo by Martin Mejia/AP Photo)

People don’t realize how much our exterior can affect our mood. If we make ourselves smile, we might feel a little better, yet if we frown, we soon get the irresistible urge to listen to Blues and weep over the days long gone. The same goes for our clothing. Many people, especially the elderly, tend to dress in the same old rags, without ever feeling the need to change something about their appearance. However, as Cue Qozop clearly demonstrates in his Spring – Autumn photoset, clothes can completely alter the appearance and the mood of the wearer. Elderly people dressed in young people’s clothes look much younger and happier. They look as if they are full of vigor and are about to set out on an amazing adventure.

Joshua Patino stands on a ladder to put finishing touches on a giant dinosaur exhibit at PAX East in the Boston Convention and Expo Center, Thursday, April 21, 2016, in Boston. PAX East, an annual celebration of gaming culture, is expected to draw tens of thousands of visitors Friday through Sunday. It's a place where serious gamers can preview unreleased video games and devices, compete in tournaments, hear live music and meet others for whom gaming is a way of life. (Photo by Elise Amendola/AP Photo)

In this June 16, 2015 photo, an Indian coachman sleeps on his Victoria horse-drawn carriage outside a stable in Mumbai, India. Drivers of Mumbai's iconic horse-drawn carriages can't imagine not plying the roads pulling photo-snapping tourists atop their kitsch-covered chariots. Yet that time is coming, thanks to a court order calling such superfluous “joyrides” a form of animal cruelty and banning them in India's financial capital from June 2016. (Photo by Rafiq Maqbool/AP Photo)

A cat jumps from a shelf to catch a light beam at the “Kis-Kis” Cat Cafe in the Siberian city of Krasnoyarsk, Russia, July 6, 2015. A local animals rights group founded the shelter for dozen of homeless cats and combined it with the cafe, where visitors can communicate with animals for hourly fee in addition to drinks, table games, books and WI-FI. (Photo by Ilya Naymushin/Reuters)

In one of the planet’s most desolate and harsh terrains, the Altai Mountains which run from Siberia in Russia down to Mongolia’s Gobi Desert, hunting with eagles is currently only practiced by a handful of Kyrgyz and Kazakhs. This form of falconry, the practice of hunting with the aid of birds of prey, can be traced back as far as 4,000 years in Central Asia. Here: after a successful hunt, a proud hunter rewards his eagle by feeding it the lungs of the prey, which is considered the most highly prized part of the animal. (Photo by Tariq Zaidi/The Washington Post)

A dramatic rise in owning exotic pets in China is fuelling global demand for threatened species. The growing trade in alligators, snakes, monkeys, crocodiles and spiders is directly linked to species loss in some of the world’s most threatened ecosystems. Here: A fennec fox (Vulpes zerda) is groomed in a pet store in central Beijing. Native to the Sahara in North Africa, the species became a popular pet after being depicted as a character in Disney’s 2016 animated movie Zootopia. Individuals can cost between $2,000–$3,000. (Photo by Sean Gallagher/The Guardian)