Well-wishers crowded the surrounding shoreline on Sunday and traversed the almost 3-kilometre length of the bridge's crowded sidewalk throughout the day as a flotilla of boats including World War II battleships and small pleasure craft cruised in the San Francisco bay waters underneath.

The bridge remained open to vehicle traffic throughout as authorities sought to avoid a repeat of the 50th anniversary celebration in 1987, when 300 000 people crammed on to the bridge at once, causing its gently arched central roadway to flatten under the weight.

"Everyone is biking and walking and looks very happy," Mary Currie, public affairs director for the Golden Gate Bridge, Highway and Transportation District, told reporters. The only damper on the festivities was the usual blanket of damp wind and fog that often shrouds the structure, and which obscured the sun until the afternoon.

The art-deco style bridge was opened in 1937 after four years of construction and at a cost of 35 million dollars. At the time it was the longest suspension bridge in the world, and held that record until the opening of the Verrazanno-Narrows Bridge in New York City in 1964. It now ranks as the world's ninth longest suspension bridge.