People have thrilled to the exploits of heroes at least since the time of ancient storytellers like the Greek writer Homer.

We’ve always needed heroes, regardless of good times or bad. Why is this so? Dr. Scott Allison, professor of psychology at the University of Richmond, answered that question in a piece he wrote for “Psychology Today.” Allison said people need heroes because they improve lives and they are inspiring. Heroes elevate us emotionally, build connections between people, and inspire us to be better than ourselves.

There is no archetype for what a hero looks like. As we’ve seen this year, heroes can be homeless people, teens delivering babies, trash haulers, first-responders going beyond the call, celebrities putting their lives on the line, and teachers and aspiring rappers thwarting deadly attacks.

24/7 Wall St. reviewed media reports of some of the year’s exceptional acts of heroism to find the nation’s most notable heroes in 2018. The following people distinguished themselves by facing danger or working to improve the lives of others.

Click here to see America’s biggest heroes of the year.