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.

Mates Jimi Hunt and Dan Drupstee dug the 650m slippery slide on a property at Helensville, northwest of Auckland and opened it this weekend as part of a festival to help combat depression.

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)

Vegas Golden Knights center Mattias Janmark (26) punches Nashville Predators center Nick Cousins (21) in a fight during the third period at T-Mobile Arena in Las Vegas, Nevada on March 24, 2022. (Photo by Stephen R. Sylvanie/USA TODAY Sports)

A soldier poses with a Hythe Mk III Gun Camera during training activities at Ellington Field, Houston, Texas in April of 1918. The Mk III, built to match the size, handling, and weight of a Lewis Gun, was used to train aerial gunners, recording a photograph when the trigger was pulled, for later review, when an instructor could coach trainees on better aiming strategies. (Photo by Harry Kidd/WWI Army Signal Corps Photograph Collection via The Atlantic)

A Filipino teacher checks a picture of a student shown on a tablet that is attached to robot during a graduation ceremony at a school in Taguig City, Philippines, 22 May 2020. At least 179 high school students received their diploma during an online graduation ceremony that was beamed live on Facebook as a measure to prevent the spread of the coronavirus and COVID-19 disease. (Photo by Francis R. Malasig/EPA/EFE)