The Golden Gate Bridge

One of the world's many marvels and feats of engineering,

right here in San Francisco

.

The Golden Gate Bridge is a suspension bridge spanning the Golden Gate,

the opening of the San Francisco Bay onto the Pacific Ocean. As part of both

US Highway 101 and California Route 1, it connects the city of San Francisco

on the northern tip of the San Francisco Peninsula to Marin County.

The Golden Gate Bridge had the longest suspension bridge span in the world

when it was completed in 1937 and has become an internationally recognized

symbol of San Francisco and California. Since its completion, the span length

 has been surpassed by eight other bridges. It still has the second longest

suspension bridge main span in the United States, after the Verrazano-Narrows

Bridge in New York City. In 2007, it was ranked fifth on the List of America's Favorite

 Architecture by the American Institute of Architects.

The Golden Gate Bridge spans the Golden Gate, a narrow, 400-foot (120 m) deep

strait that serves as the mouth of the San Francisco Bay, between San Francisco

at the northernmost tip of the San Francisco Peninsula, and the Marin Headlands

at the far southern end of Marin County. Although close by proximity, the two sides

of the strait are separated by significant natural obstacles. Crossing the strait directly

by boat is dangerous because of strong currents and lack of suitable landings.

Ocean tides drive an average of 528 billion gallons (2 billion cubic meters) of water

every six hours, at peak currents exceeding 5.6 miles per hour (2.5 m/s).

Circumnavigating the Bay, however, involves a trip of several hundred miles and

crossing several major rivers.