With more than 400 units in the National Park System, trying to zoom in on any one particular park for a visit can be a challenge. Over the past 12 months the Traveler has "explored" quite a few parks, and we list those stories here to help you plan your next national park adventure.

In the early 1800s, following in the footsteps of Lewis and Clark, a host of scouts, soldiers, trappers and traders began venturing from St. Louis, eager to explore and exploit the natural riches to be found in the wilderness of the West. It was America’s new economic frontier. The expansion of the fur trade would introduce new cultures and trading partners to farsighted business entrepreneurs.

Quiet spreads across Big Bend National Park during the winter months, both in the lack of visitors to this grand rumpled slice of parkland in southwestern Texas as well as audibly. Silence pervades the Chihuahuan Desert, both day and night. The wind blows, but it’s felt more than heard. The Chisos Mountains are quiet as well. The cactus and Ocotillo plants look drab and thornier than usual without their brilliant spring blooms to grace and hide the sharp spikes. Cooler temperatures prevail, and occasional snow- or hail-storms punctuate the season.

An oddly familiar music greeted me as we pulled up to our reserved site in Gallo Campground, located in a side wing of Chaco Canyon’s buff-colored sandstone cliffs. That sounds like a white-crowned sparrow, I thought as I carried our tent to the 12-foot-square sandbox that would be our sleeping spot for the next four nights. I got out binoculars and, sure enough, there were the telltale white-and-black head stripes that identified it as my favorite mountain songster. But here in the desert? In mid-October? Already this national historical park in New Mexico, which my wife and I and a friend from Albuquerque were visiting for the first time, was surprising me.