Fort Union National Monument Visitor Center
Address: 3115 NM Highway 161, Watrous, NM 87753
Fort Union was the largest military post in the 19th-century Southwest: three successive forts guarded the junction of the Santa Fe Trail's two branches from 1851 to 1891, and the great adobe ruins still stand beside deep wagon ruts worn into the prairie.
Walk the trail among the chimneys and wall foundations and step into the trail ruts; young kids can earn a Junior Ranger badge. For a challenge, study the museum and take the full ruins loop at sunset when the adobe walls glow.
Coordinates: 35.90505, -105.01153