What's the main difference between a "spa" and a "hot spring?"

Native speaker’s answer
Rebecca
That's a good question! The difference is that a "hot spring" is water heated from within the earth, a "spa" is usually artificially heated water, and they provide different treatments like massages. Although sometimes a "spa" is centered around a "hot spring." Ex: The hot springs in Iceland are very famous. Ex: I feel like I need to go to a spa and get a massage this weekend.