When we think of national parks in the U.S., we think of natural grandeur: the granite cliffs of Yosemite, perhaps, or the twisting canyons of Zion. The National Park Service (NPS), however, manages 431 units of staggering diversity—some as small as the one-room Thaddeus Kosciuszko National Memorial in Pennsylvania. Helping people discover and navigate its wide ranging locales has been a foundational goal and challenge since the early 1900s, when…