The San Luis Valley in southern Colorado still looks much as it did one hundred, or even two hundred, years ago. Blanca Peak, at 14,345 feet the fourth-highest summit in the Rockies, overlooks a vast openness. Blanca, named for the snow that covers its summit most of the year, is visible from almost everywhere in the valley and is considered sacred by the Navajo. The range that Blanca presides over, the Sangre de Cristo, forms the valley’s eastern side. Nestled up against the range just north of Blanca is Great Sand Dunes National Park. The park is an amazement: winds from the west and southwest lift grains of sand from the grasses and sagebrush of the valley and deposit the finest ones, creating gigantic dunes. You can climb up these dunes and run back down, as I did as a child on a family road trip and I repeated with my own children fifteen years ago. The valley tapers to a close down in New Mexico, a little north of Taos. It is not hard to picture the indigenous people who carved inscriptions into rocks near the rivers, or the Hispanic people who established Colorado’s oldest town, San Luis, and a still-working system of communal irrigation in the southeastern corner, or a pioneer wagon train. (Feral horses still roam, as do pronghorn antelope and the occasional mountain lion.)