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.

For more than a century, the Barcelona skyline has been graced (or marred, depending on who’s talking) by the spectacle of the Basilica designed by Anton Gaudi, first started in 1882. If you want to know what it’ll look like when finished, don’t fret — 2026 is right around the corner. Or you can watch this video, released last week on YouTube by Basílica de la Sagrada Família and titled simply “2026 We Build Tomorrow,” a 3-D artists’ rendering of the building stages through completion.
(If 144 years sounds like a long time to finish a cathedral, keep in mind that there were decades that they didn’t work on it — and that Notre Dame de Paris took 182 years, although the 13th century Parisians didn’t have diesel-powered industrial cranes.) Now, if only the video could show us what the admission and hours will be in 2026 (and how to avoid the inevitable long lines).

A freediver uses weights, yoga and camera tricks to create the illusion of walking underwater for a film which took three years to shoot and was completed in 2013 in El Hierro, Canary Islands. Like a scene from a Hollywood science-fiction movie, this trick footage shows a man apparently walking on water. The underwater film was shot by biologist Armiche Ramos and brothers Armando and Francisco del Rosario, who used their expertise in freediving to create the illusion. No computer graphics were involved in the production, with the team relying solely on their own skills – and a few hidden secrets. (Photo by Ocean Brothers/Barcroft Media/ABACAPress)

A newly-hatched baby sea turtle makes its way into the Mediterranean Sea for the first time, as part of the Israeli Sea Turtle Rescue Center's conservation program, at a beach near Mikhmoret north of Tel Aviv, Israel September 9, 2019. Green turtles are endangered worldwide, the World Wildlife Fund says. Among other hazards, they are threatened by hunting, human encroachment on the beaches where they nest, and pollution of their feeding grounds offshore. According to the Israeli rescue center, only about 20 female green turtles nest along the Israeli Mediterranean coast during a breeding season that usually lasts from May until August. (Photo by Amir Cohen/Reuters)

Russian riot policemen beat young PREGNANT female anti-Putin activist during a protest rally against the Presidential inauguration of Vladimir Putin on May 6, 2012 in Moscow, Russia.

Commander, a German Shepherd adult (L) and Ziva, a German Shepherd puppy attend as American Kennel Club announces Most Popular Dogs in the U.S. at American Kennel Club Offices on February 28, 2012 in New York City. (Photo by Gary Gershoff/Getty Images for AKC)

“Snowflake (c. 1964 – November 24, 2003) was an albino gorilla. He was the only known albino gorilla so far, and the most popular resident of the Barcelona Zoo in Catalonia, Spain. Originally named Nfumu Ngui in Fang language ("white gorilla") by his captor, he was then nicknamed Floquet de Neu (Catalan for little snowflake) by his keeper Jordi Sabater Pi. On his arrival to Barcelona where he was given an official reception by the then Mayor of Barcelona, Josep Maria de Porcioles, in November 1966, he was called Blancanieves (“Snow White”) in the newspaper Tele/Exprés. But he became famous with the name given to him by Sabater when National Geographic Magazine featured him on the main page in March 1967, with the English name Snowflake. This name spread among the press (Stern, Life, Paris-Match) and was later translated to Spanish as Copito de Nieve. Sabater himself called the gorilla Floquet or Copi, and in the later years Nfumu. The asteroid 95962 Copito, discovered by Catalan astronomer J. Manteca, is named in his honour”.

A huge atlas moth, with a wingspan of more than 9in, photographed on an areca nut plantation in Sirsi, India. (Photo by Uday Hegde/Close Up Photographer of the Year)