Pretty much every year from first grade to my senior year, I had a Social Studies class that went through history chronologically. Each year would focus more on one thing or another. The history of the Americas, or systems of government, or wars, or kings and queens, or local history, or the role of religion in history. But each time we'd start at some point and progress forward through the years.
And every year, as summer loomed, the teacher would find that we were behind schedule, and as we hit the 20th Century, things would get covered more and more scantily. As a result, I find I learned a fair amount about the American Revolutionary War, the Age of Exploration, the Holy Roman Empire, the Industrial Revolution, the British monarchy, the Civil War, and a host of other subjects, but I know almost nothing about the latter half of the twentieth century.
World War I was always covered fairly well, and I got a moderate exposure to the temperance movement, the Roaring Twenties, and Prohibition. The Great Depression and the New Deal always got covered quite thoroughly, as did the League of Nations. After that we got very hazy. World War II, and the events leading up to it, were always covered only in broad strokes. I knew who was on which side, the leaders, the Nazi atrocities, and Pearl Harbor, but beyond that, very little. I'd heard of D-Day, but I don't think I ever had a history teacher or text tell me what it was; I only knew what little I'd picked up by osmosis from popular culture.
(In fact, what prompted this post was reading about Peter Jackson's plan to make a remake of the movie The Dam Busters. The article mentioned a little about the military action upon which the movies are based, but didn't say how it turned out. I had never heard of this operation, not at all, and I soon realized, I'd never heard of any military action in WW2 except for those I heard in passing from wargamer or historian friends and associates, or picked up in movies and books and TV shows, with the one glaring exception of Pearl Harbor. Based on my schooling, I know more about Drake's actions against the Spanish Armada than about all of WW2.)
As for after World War II, it gets even worse. Not once in any of my history classes did we talk about anything after WW2 except a brief discussion of the formation of the United Nations. Never did we cover the Korean War, the Vietnam War, the civil rights movement, the atrocities in Africa and Oceania, tensions in the Middle East, the Kennedy assassination, the Cold War and McCarthyism, the Watergate scandal, the Space Race, Cuba and other spreads of communism, or anything else going on between the end of World War II, and the "current events" things we were studying as they happened. The first major historical event after World War II that I learned in school was the Energy Crisis.
Naturally, I've filled in this gap somewhat outside of, and after, school. I wouldn't do very well on a trivia category covering the third quarter of the twentieth century, but I wouldn't be hopelessly lost. Even back in elementary school I probably knew more about the Space Race than my teacher did anyhow. But there are still unfortunate gaps. It's not like I really need to know those things particularly better than I do; but it's still odd that I know them less than I do other times that I need to know about even less.