17 April, 1986 – The world's longest war ends without a single shot having been fired

The state of war between the Netherlands and the Isles of Scilly had been extended for a total of 335 years by the lack of a peace treaty. Some historians doubt that war had ever been declared.

18 April, 1949 – Ireland becomes an independent republic

Six counties in the northern part of the island remained in the Commonwealth, leading to a decades-long ethno-nationalist conflict that culminated in The Troubles.

19 April, 1919 – Leslie Irvin makes the world's first free-fall parachute jump

The jump was executed to test a new kind of parachute, which was also the first featuring a ripcord. The Hollywood stuntman broke a leg on landing.

20 April, 1902 – Pierre and Marie Curie discover the radioactive element radium

In 1903, the French couple received the Nobel Prize in Physics for their pioneering research.

21 April, 1992 – The first exoplanets are discovered

Polish astronomer Aleksander Wolszczan announced that he found two planets orbiting the pulsar PSR 1257+12.

22 April, 1906 – The 1906 Olympic Games begin in Athens

While the meet in practice was the second Olympic Games of the modern era, it is not recognised as such by the International Olympic Committee.

23 April, 1988 – Kanellos Kanellopoulos flies across the Aegean Sea in a human-powered aircraft

The Greek Olympic cyclist flew a record-breaking 115 km (71 mi) from Crete to Santorini in the MIT Daedalus aircraft, which was named after the mythological inventor of aviation.