On May 28, 1937, the Golden Gate Bridge officially opened to traffic. It was the longest suspension bridge in the world at the time of its opening and was dubbed a “Wonder of the World” structure. The Golden Gate is a narrow passage of water that connects San Francisco Bay to the Pacific Ocean. Formed by the erosive water from the Sacramento and San Joaquin Rivers during the Ice Age, the deep channel features powerful tidal currents. Dense fog forms over the region as cool, moist, ocean air travels inland and meets warmer temperatures. The frequent thick fog may help to explain why several seasoned explorers failed to discover the Golden Gate until 1769.