Which event is commemorated on June 18?

June 18 is commemorated for the Battle of Waterloo, a significant event in European history that took place in 1815. This battle marked the decisive defeat of Napoleon Bonaparte, which ended his rule as Emperor of the French and ultimately led to the restoration of a balance of power in Europe. The victory at Waterloo was a turning point, cementing the United Kingdom's status as a dominant military power in the 19th century and contributing to a long period of relative peace in Europe known as the Congress of Vienna.

The other events mentioned, while important in their own right, do not correspond to June 18. The signing of the Magna Carta occurred in 1215, but that date is more commonly associated with June 15. World War I began on July 28, 1914, and is not associated with June 18. The founding of London, attributed to the Romans in AD 43, does not have a specific commemorated date and certainly isn’t June 18. Therefore, the Battle of Waterloo is the correct event linked to this specific date.