CAPTCHAs exist to tell humans apart from bots. Around 2007, researcher Luis von Ahn had an idea: one of the two words to type came from old books or newspapers that recognition software couldn't read. Millions of users thus deciphered entire archives, word by word, without realising it. Acquired by Google, the system helped digitise whole libraries.
In 1843, inventor Alexander Bain patented a way to send images over telegraph wires using synchronized pendulums. By the 1860s, a commercial fax service was already linking cities. The telephone wasn't patented until 1876, more than three decades after that first fax patent. The fax is really a child of the telegraph age.
On 8 October 1958, in Stockholm, 43-year-old Arne Larsson received the very first implanted pacemaker. The device, designed by engineer Rune Elmqvist and implanted by surgeon Åke Senning, worked for only a few hours and had to be replaced. Larsson went on to receive more than twenty pacemakers in his lifetime. He died in 2001 aged 86, outliving both the engineer and the surgeon.