In Mortero Wash in Anza-Borrego Desert State Park, the volcanic desert landscape posed a significant challenge for travelers, yet John D. Spreckels pursued his ambition to build a railroad across this rugged terrain to connect San Diego to lucrative Eastern markets. Engineers scoffed at the plan as "the impossible railroad," and from its founding in 1906 until Spreckels drove the final golden spike on November 15, 1919, the San Diego and Arizona Railway nearly lived up to that reputation. One 11-mile section through nearby Carrizo Gorge alone required 17 tunnels and 14 wooden trestles, and even today nature only grudgingly yields to travel through this harsh landscape.