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.

Отава Ё – Яблочко (Otava Yo – Yablochko; Russian: Яблочко, “Little Apple”). Yablochko is a Russian folk song of chastushka style and dance, traditionally presented as sailors' dance. The choreographed version of the dance first appeared in the 1926 Reinhold Glière ballet The Red Poppy and from there is known in the West as the Russian Sailors Dance.

South Korean girl group KARA arrive during the 21st High1 Seoul Music Awards at Olympic gymnasium on January 19, 2012 in Seoul, South Korea. (Photo by Chung Sung-Jun/Getty Images)

#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).

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

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.

A receptionist dinosaur robot performs at the new robot hotel, aptly called Henn na Hotel or Weird Hotel, in Sasebo, southwestern Japan, Wednesday, July 15, 2015. From the receptionist that does the check-in and check-out to the porter that’s a stand-on-wheels taking luggage up to the room, the hotel, that is run as part of Huis Ten Bosch amusement park, is “manned” almost totally by robots to save labor costs. (Photo by Shizuo Kambayashi/AP Photo)