The Persian War and specifically the Battle of Thermopylae Pass is usually covered pretty well, isn't it? I teach U.S. and World History, though certainly not in a standard setting, and I always give those a reasonable amount of attention (and I don't care for military history). I remember learning about Thermopylae in my own high school World History class--I distinctly remember thinking that it was the single coolest thing ever to happen.
My history class regarded the Battle of Thermopylae little more than a piece of propaganda. It included a lot of Arcadians, far more than Spartans, and the Persians defeated them with a bit high, but nothing too crazy, causalities. During that war, the Naval defeat of the Persians was infinitely more important than the battle of Thermopylae. Probably one of the few Naval battles were 'knowing the terrain' really was hugely important, at least I know of.
Battle of Wizna is a tad more impressive.
Worse: I never had any actual
battles covered in any K-12 class I ever took that mentioned ancient Greek or Roman history or mythology, except for the Trojan Horse's role in ending that particular war (in
literature class, not history class), and some vagueness about the sacking of Rome by the Vandals. Alexander the Great was discussed, of course, as was the prowess of Julius Caesar, but absolutely none of their actual battles or tactics were even mentioned in passing.
I learned about Thermopylae, the whole Antony/Cleopatra thing, the Punic Wars, the rape of the Sabine women, and Archimedes' role in the (failed) defense of Syracuse from outside sources, mostly pleasure reading and the Internet. (I also learned an insane variety of non-age-appropriate mythology, literature, and history from my father. I knew at age 6 that the reason Macduff kills Macbeth in the play is because, while "No man of woman born can harm Macbeth," Macduff was "from my mother's womb untimely ripp'd." I knew the basic outline of the mythical founding of Rome and the story of Achilles by age 4 at least.)
How much attention is paid to the various Israeli conflicts, the Soviet occupation of Afghanistan, and the war in the Falklands by the US school system?
In the schools I went to? Zero.