Although is a word you use when you're connecting two ideas that seem to pull against each other. It introduces a contrast or surprise between what you'd normally expect and what actually happens.

When you say “Although it was raining, we still went to the park,” you're acknowledging that rain usually keeps people inside, but in this case, something different happened. The word signals: “Here's one thing that's true, BUT here's another thing that's also true, and they don't quite match up the way you'd think.”

You'll see although at the beginning of sentences or in the middle: “We lost the game, although we played our best” or “Although she studied hard, the test was still difficult.” Notice how it introduces the part that seems to work against the other idea.

The words though and even though work similarly. Though is a bit more casual, while even though adds extra emphasis to the contrast. “Even though I was exhausted, I finished my homework” stresses just how tired you were, making it more impressive that you completed the work.

Writers use although to show life's complications: things aren't always simple, and two opposite-seeming facts can both be true at once.