In the January 1941 edition of Popular Science a fantastical invention was profiled:
A leash attached to a spring-operated reel is a new wrinkle for dog owners. Encased in a light but sturdy aluminum housing, the reel carries twelve feet of waterproofed leash strong enough to hold a great Dane yet light enough for use with a Pekinese. A hook forming part of the housing allows the owner to hold the device securely, while the dog is free to run for a distance of twelve feet. As he returns nearer to his owner, the spring reel winds up the leash cord to prevent it from becoming tangled. A button-con-trolled lock makes it easy to stop the dog at any time as he is running out the leash, and to keep him in hand.
What’s fantastical today that will be commonplace in 70 years?