Exhibit Area 1
(Plaza area)
Welcome Sign [main directory]
How the Bridge Spans the Golden Gate
Bridge Aesthetics - Art Deco on a Grand Scale
Tall and Strong - The Bridge Towers
Steel, Fog, Salt, Rust, and Paint

Exhibit Area 2
(near flagpole)
How the Bridge Vibrates

Exhibit Area 3
(West side of Bridge near underpass)
Historic Preservation: Lattice Strut Retrofit
Historic Preservation: Isolator Seismic Retrofit

Exhibit Area 4
(inside Battery area)
History: Design and Construction of the Bridge
Suspension Cable Tension vs. Tower Height
Battery Lancaster - Defending the Golden Gate

Exhibit Area 5
(along bike path to lower parking lot)
Bridge Deck Aerodynamics
Bridge Deck Torsional Resistance Retrofit
Wind Speed and Wind Pressure

Exhibit Area 6
(near Pavillion)
LIFETILES: animated construction of the Bridge
Braille / Tactile Model of the Bridge

Project Partners

Golden Gate Bridge,
Highway and Transporation District


Consortium of Universities for Research
in Earthquake Engineering

Main Menu : Exhibit Area 2


When it's foggy you can hear the sound from the south tower instantly by telephone, 415-202-3809. Then, wait about 2 seconds to hear the sound waves reach your ears through the air, traveling a little faster than a jet airliner. The south tower foghorn sounds a deep, loud note for 2 seconds, then it repeats in 18 seconds. Another foghorn at midspan between the towers sounds a pair of high-pitched notes.

Fog is formed when the moist air over the ocean is cooled by cold water currents along Northern California’s coast. The water vapor cools and condenses into tiny water droplets – fog.

Why does the fog come through the Golden Gate?
It is the only sea-level gap in the coastal mountain range for hundreds of miles. It is a canyon cut through the mountains by an ancient river. Water stored as ice melted as the last Ice Age ended, raising the sea level. Today, the bottom of that canyon is over 300 feet (90 meters) below the waves.

More Images

Photo of Bridge foghorn
Fog Horn Timing Chart - Shows the difference in time intervals of the fog horns at the South Tower of the Bridge and at midspan.
average number of hours of fog since 1937
(based on hours of foghorn operation since 1937)
Jan = month 1

Fog is most common in the summer, when the air over the interior land heats up more than over the ocean. Warm air is less dense and exerts less pressure than cooler air, allowing the cooler ocean air to push its way in through the Golden Gate.

All images property of the Golden Gate Bridge, Highway and Transportation District (unless otherwise indicated).

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Last updated: 11.08.12