In WWI, many British naval ships were painted with “Dazzle Camo”, a camouflage scheme designed not to make them hard to see, but rather to create a confusing perspective that made judging ship type, speed, and direction difficult.
When Archduke Franz Ferdinand was murdered in his car – triggering the start of World War One – the number plate of his and his wife’s car read “AIII 118”. 11/11/18 was the date when the armistice was finally signed.
The phrase “The First World War” was used as early as 1918, by a journalist who felt it would not be the last.
Tolkien developed a secret code with his wife in WW1, strictly illegal, so that she could track his progress on the map.
Upon discovering an abandoned printing press in Belgium during the first world war, British soldiers decided to start publishing their own satirical newspaper from the trenches.
The Spanish Flu was named that because it’s effects on countries involved in WW1 were censored for morale. Spain was neutral and thus papers reported on the flu hitting Spain, making people believe Spain was hit especially hard.
Jean Jaurès, a French socialist, predicted world war one and tried to organize global strikes to prevent it. He was assassinated before his plans could be realized.
Andorra declared war on Germany during WW1, but didn’t send any soldiers because they didn’t have an army. At the Treaty of Versailles, Andorra was forgotten and technically remained at war with Germany, until the two countries declared peace in 1958.