Hydrogen is the oldest element in the Universe: it first appeared more than 13 billion years ago. But it was not until two centuries ago that hydrogen was first isolated and discovered.
Hydrogen is the simplest element that exists. It is present in abundance in the Universe. It is found in every star, including the Sun, which draws its energy from the transformation of hydrogen into helium during a thermonuclear reaction.
Its discovery by Cavendish in the 18th century was a major scientific breakthrough that led, among other things, to the discovery of the exact atomic composition of water for the first time in history.
This discovery opened the way for the first applications of hydrogen, particularly in the field of transportation—from the first hot-air balloons to the first motorized vehicles.