Oregon Mountain once stood where this site is, a mound of earth imagined as large as 6 football fields and two miles high. In the quest for gold, hydraulic mining dissolved 90% of it, and from 1851 until 1933 the mountain was slowly washed down the Trinity River by monitors in what was the largest hydraulic mine in the world. The remaining 10% was later washed away in search of another kind of gold—travel, tourism, and trade—as the California Department of Transportation liquidated what was left to make a road cut. After 5 years of day-and-night washing with monitors, the mountain was eliminated, and in 1939 the last segment of Highway 299 was finished, connecting the valley and coast.