Horseshoe arches of 12-by-12-inch California redwood timbers still support this tunnel cut beneath the Continental Divide at 11,600 feet for the Denver, South Park & Pacific Railroad. Nominally headed for the Pacific, this narrow-gauge line exhausted its funds and energy digging the first tunnel under Colorado's Continental Divide and never got beyond Gunnison County. Abandoned in 1910 and sealed off, the tunnel is celebrated in a two-room museum in the restored West Portal Depot. Tunnel Gulch Tank has been restored along an auto road using the twisting roadbed of the DSP&P. The Palisades, a 33-foot-high, 452-foot-long, hand-fitted stone retaining wall two-and-one-half feet thick allowed the trains to cross the face of a sheer granite cliff. Dry-laid rubble cut from the cliff widened a narrow natural shelf to accommodate the track. This is perhaps the largest example of stone railroad construction in the American West.