Many systems count time as seconds elapsed since 1 January 1970. Stored in 32 bits, that counter hits its limit on 19 January 2038 at 03:14:07 UTC, then wraps around to a negative value, as if jumping back to 1901. Modern systems use 64 bits, enough for hundreds of billions of years, but older embedded devices remain at risk.
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.