Donald Trump marked his 80th birthday by hailing an initial agreement to end the Iran war and staging a cage-fighting show on the White House South Lawn.
A large-scale Russian attack on Ukraine has killed five rescue workers in Kharkiv and four people in Kyiv, as strikes set apartment buildings ablaze and sparked a fire at one of the country's most significant religious landmarks.
How did the light-emitting diode change the world? And, come to mention it, might it perversely actually prompt us to puff more carbon dioxide into the atmosphere?