Some 6 miles [10 kilometers] west, experience the antithesis of an interstate: the Historic Columbia River Highway. The 17-mile-or-so [27 kilometer] stretch between here and Troutdale is the longest remaining portion of this scenic route, built between 1913 and 1917. Its purpose, in the words of its supervising engineer, Samuel Lancaster, was "to find the beauty spots, or those points where the most beautiful things along the line might be seen to the best advantage...." In addition, the slow, twisting road itself augments the beauty of the gorge with stone guardrails, arched bridges, rock walls, and lookout points that are testaments to the fine art of stone masonry.The land along the highway is loaded with waterfalls, lush forests, state parks, hiking trails, gorge overlooks, and picnic areas. About 3 miles [5 kilometers] from Warrendale is the Oneonta Gorge, a split in the cliff that rises hundreds of feet overhead and averages about 20 feet [6 meters] across. In the summer, when Oneonta Creek is low, visitors willing to get their feet wet can hike a short way up this enchanting fissure to the waterfall at its end. Mosses, ferns, and other plants that thrive on the gorge's perpetually cool, moist conditions thickly coat the basalt walls. Some are rare, and a few are unique to Oneonta Gorge, so the Forest Service has designated the gorge as a "special botanical area."