Few days ago xkcd posted one of my favourite sketches that will definitely end up in a future talk (professional or outreach). In it, the main stick character is experimenting with fusion cuisine by heating four cups of heavy water (which is like the regular water, but with deuterons instead of hydrogen 1H.) The process of converting hydrogen into heavier elements is what powers the stars we see in the night sky! Iron is the endpoint of that process in the cores of the stars, since heavier elements are mainly created by neutron captures.