At the turn of the 20th century, the nations of Europe had been at peace with one another for nearly how many years?

The correct answer to this open question is the following.

At the turn of the 20th century, the nations of Europe had been at peace with one another for nearly how many years?

The nations of Europe had been at peace with one another for nearly 100 years.

We are talking about the moment European nations signed the agreement during the Congress of Vienna in 1815, the so-called "Concert of Europe," until the beginning of World War I, in 1814, after the assassination of Archduke Franz Ferdinand, of the Austria-Hungary Empire.

One of the goals of the Congress of Vienna (1814-1815) was to restore Europe to the way it was before the French Revolution and Napoleonic Wars.

aug 15, 2012 - although van leeuwenhoek was not the inventor of the microscope, he advanced it more he loved to grind and focus a new lens in order to see the unseen world. most of leeuwenhoek's microscopes were silver. in a simple but significant experiment (1668), he demonstrated that worms found on