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.

In this April 4, 2014 file photo, a community policeman kicks a man who they alledge participated in an ambush against them near the town of La Concepcion, Mexico. The vigilante force was set-up by affected communities opposed to the construction of the La Parota hydroelectric dam. Two vigilantes were injured and one died. (Photo by Bernandino Hernandez/AP Photo)

In this Thursday, May 8, 2014 photo, guests look down from the Tilt!, a new tourist attraction that provides guests a unique view of the downtown area from the 94th floor of the John Hancock Building, after it was unveiled in Chicago. People hold onto handrails as the glass and steel facade tilts forward 30 degrees. (Photo by Ashlee Rezin/AP Photo/Sun-Times Media)

A dead whale is seen on the shore of the Ipanema beach in Rio de Janeiro, Brazil November 15, 2017. A biologist, Rafael Carvalho, said on Wednesday the whale appeared to have been dead for a few days. Authorities were urging beachgoers who had flocked to Ipanema on a national holiday to stay away from the animal. However, many were spotted near the carcass with some people playing in the water nearby. The whale is approximately 39 feet (12 metres) long and weighs about 25 tonnes. (Photo by Pilar Olivares/Reuters)

These photos and video were taken in the Russian city of Astrakhan on the evening of June 7th, 2012. (Photo by Maxim Korotshenko)

#Resistiré 2020 (# I will resist 2020), the hymn recorded by more than 30 Spanish artists to beat the coronavirus together. Participating in the hymn: Alex Ubago, Andrés Suárez, Álvaro Soler, Blas Cantó, Carlos Baute, Conchita, David Bisbal, David Otero, David Summers, Despistaos, Diana Navarro, Dvicio, Mariposa Effect, Hall Effect, Ele, Georgina, India, Jose Mercé, Josemi Carmona, Manuel Carrasco, Melendi, Mikel Erentxun, Nil Moliner, Pastora Soler, Pedro Guerra, Pitingo, Rosana, Rozalén, Rulo, Sofía Ellar and Vanesa Martín. Promoted by Cadena 100, all these musicians and artists come together under the production of Pablo Cebrián to get this Resistiré, with which all funds will be for the benefit of Cáritas (Caritas Internationalis is a confederation of 165 Catholic relief, development and social service organizations operating in over 200 countries and territories worldwide. Collectively and individually, their claimed missions are to work to build a better world, especially for the poor and oppressed).

The Slauerhoffbrug (English: Slauerhoff Bridge) is a fully automatic bascule bridge (aka tail bridge) in the city of Leeuwarden in the Netherlands. It uses two arms to swing a section of road in and out of place within the road itself. It is also known as the “Slauerhoffbrug ‘Flying’ Drawbridge”. A tail bridge can quickly and efficiently be raised and lowered from one pylon (instead of hinges). This quickly allows water traffic to pass while only briefly stalling road traffic. The deck is 15 m by 15 m. It is painted in yellow and blue, representative of Leeuwarden's flag and seal.