Happy 100th birthday to our National Park Service, the federal agency that oversees and protects hundreds of national parks, monuments, preserves, recreation areas and other places worth seeing and saving.

The history of these parks is complicated, as histories usually are. They’re all infused with the countless forcible removals of Native Americans — Yosemite Valley was still home for some indigenous people until just a few decades ago — and one of their most important early proponents also helped inspire the Nazis. Today their maintenance is billions of dollars behind, and researchers have found the effects of climate change are decimating the conifers in the Rocky Mountains and poisoning the wetlands in the Everglades.

But these parks still protect thousands of square miles of every biome the continent has to offer. They span deserts and forests and rivers, and they hold our highest mountains, our lowest basins and our oldest trees. They gave an example for other countries to follow, setting aside their own natural treasures. As longtime National Park Service specialist and Nez Perce member Otis Halfmoon put it, “they are truly the gems of America.” They also do something less visible but crucially important, in my mind: They show us how small we are.

A little humility seems all the more valuable to me these days. Now go visit some parks and help the National Park Service take care of them.

(If you don’t recognize these photos, they’re tiny pieces of Great Sand Dunes National Park and Preserve in Colorado, Yosemite National Park in California, White Sands National Monument in New Mexico, and Hot Springs National Park and the Buffalo National River here in Arkansas.)