The Southeast Colorado region, including Big Timbers, was once a great inland sea, and prehistoric migrating groups established the first transportation routes across the Santa Fe Trail by following game and seasonally available edible plants. At John Martin Reservoir State Park, a track was found when the water receded, visitors can explore the shoreline to see sea fossils, and the park is one of the few public places to walk across the actual Santa Fe Trail. On November 13, 1806, Zebulon Pike and his men camped along Lamar's Willow Creek, and Willow Creek Park later became Colorado's first Works Progress Administration project, built from 1933 to 1938 as part of President Franklin Roosevelt's program to provide employment, conserve natural resources, and stimulate the economy during the depression. Charles and William Bent and Ceran St. Vrain received a trading license in 1833 for Bent's Fort, an adobe post built where the Mountain Branch of the Santa Fe Trail crossed the Arkansas River that became a regional center for trappers, buffalo hunters, Plains Indians, and Mexican trade. In 1846, as the Mexican War approached, Bent's Fort became a military rendezvous for America's conquest of Mexican territory, but by 1848 trade had declined, and unsuccessful attempts to sell the fort to the army, lack of firewood, and poor grazing led Bent to relocate to Big Timbers; in 1852 he removed his goods, burned the fort with gunpowder kegs, and left. Bent had built a small log trading house at Big Timbers sometime before 1844, and in 1853 Bent's New Fort, a stone fort on a rocky knoll overlooking the Arkansas River, was built two miles south and seven miles west of Big Timbers museum to serve as a trading post and army supply center. In 1860 the army built Fort Wise, later Fort Lyon, a mile west of Bent's New Fort on the river bottom, and it became a distribution center for commodity goods to the Indians. Both abandoned Bent's forts were later used as stage stops, many kinds of freight and passenger vehicles traveled the Santa Fe Trail, and new routes branched from the Mountain Branch, including the Purgatoire Stage Route, the Granada-Fort Union Military Freight Route, the Army Cutoff, and part of the Cimarron Branch. On February 14, 1880, a Santa Fe newspaper marked the arrival of the railroad by declaring, "The Old Santa Fe Trail Passes Into Oblivion."