1578: The Roman Catacombs were said to have been rediscovered by accident when some workmen digging for pozzolana earth (excellent for building purposes) uncovered a burial chamber.
1910: The Union of South Africa came into being as a Dominion with the unification of the former Boer republics of the Transvaal and the Orange Free State with the British colonies of Natal and the Cape.
1911: The RMS Titanic was launched at the Harland and Wolff shipyard in Belfast. She was completed in March 1912 and began her doomed maiden voyage on 10 April.
Compiled by Julian Humphrys – You can follow Julian on Twitter @GeneralJules