In 1864, a peculiar book called "Spectropia" offered Victorian readers a scientific way to summon ghosts. As the Smithsonian reports, author J.H. Brown created this "toy book" to combat what he called ...

Brainteasers are a delightful way to challenge your wits – and optical illusions can work wonders ... you're going to see something really cool if you like what you see, share it with a friend." ...