For 130 years, the kilogram was defined by a small cylinder of platinum and iridium, kept under three glass bell jars near Paris. The problem: its official copies drifted away from it by tens of micrograms over the decades. Since 20 May 2019, the kilogram has been defined using a constant of nature, the Planck constant, which is the same everywhere in the universe.
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.