Over the years I've been an occasional history buff and one event that often attracts my attention is the American Civil War. I've read a number of books. Currently, I'm listening to the Civil War Podcast which is a comprehensive look into the Civil War. Its only fault is it is almost too comprehensive as they are still in 1862 and they are 237 episodes into the series. However, it is a great series and I heartily recommend it if you are at all interested in the Civil War.
Recently I've discovered two conflicts in the region I knew nothing about, which surprised me quite a bit when I discovered their existence.
First, between 1866 and 1870, there were multiple invasions by Irish Civil War veterans into Canada after the war. They were trying to strike a blow for Irish independance by attacking British holdings. These attacks were collectively called the Fenian Raids. I had no idea this ever happened.
Second, I didn't know that France invaded Mexico while the Civil War was raging up north. What started out as a joint France, Britain, and Spain operation was reduced to just France as they invaded in 1862. Franch ostensibly had a declared reason of invading to reclaim unpaid debt to Mexico, but in reality, they wanted to overthrow the republic and place an Emperor in power who would align with France and be less friendly toward the US. Obviously, the timing intentional so that the distracted United States would not seek to enforce their Monroe Doctrine. France was less than successful and things dragged on so long that France lost momentum and the post-war United States was able to apply enough diplomatic force to get France to pull out its troops in 1867. France's Mexican Imperial allies were then left to fight alone and lost the war to Republican Mexico.
History can be so fascinating when you starting finding all the tidbits that get left out of the broad sweeps of history textbooks.