Things we thought we'd never live to see

Transistors (remember them?) were derided as a scientific curiosity of no practical use. They were too small, couldn't handle the currents needed and so on... Within ten years or so from the invention they started appearing in radios. Then integrated circuits came in, effectively a collection of miniature transistors, and we sit typing at a machine containing the equivalent of millions of the little things.

Pocket calculators, back in the 1950s, were often mentioned when schoolchildren were asked what they hoped would be invented. The idea that you might have a battery-powered calculating machine the size of a packet of gaspers never failed to produce guffaws from our wiser, older teachers. They also pooh-poohed the suggestion that removing longwinded pen-and-paper calculations might actually make mathematics easier.

Space flight - don't be so ridiculous, we were told in 1955. The amount of fuel needed to lift a rocket even into Earth orbit would be too heavy for the craft to lift off in the first place. In 1956 the USSR put a craft into orbit. Sputnik, if you wish to look it up.

Amazon deforestation could never happen. Every time they tried to build a road, by the time they'd finished surfacing it the jungle would have invaded the other end, obliterating all trace of man's puny efforts.

In 1964 a new town was planned on the basis that "for the forseeable future" oil would be the cheapest convenient source of energy. Miles of new roads were laid for the expected number of new cars. We got the cars and also in 1973 the oil crisis. Arab oil states had finally decided to act in concert instead of selling their natural resources for pennies per barrel.

Every time I hear an expert assure that "it could never happen" I start counting the weeks until the impossible occurs. Past examples are too numerous to mention in full. The list above is just a sample.