Remains of the warden's home on Alcatraz Island.

A garden near the warden's home on Alcatraz Island.

A Western Gull finds a perch in an Alcatraz garden near the warden's home.

Western Gulls living in the warden's home on Alcatraz Island.

Western Gull chicks on a stairway at Alcatraz Island. Alcatraz is home to one of the largest colonies of Western Gulls on the United States western coast.

Western Gull disputing landing zone with a colleague on Alcatraz Island.

A tour boat cruises offshore from Alcatraz Island.

The Ferry Building - a San Francisco landmark along the Embarcadero.

San Francisco geometry lesson - skyscrapers and artwork intermingle for a Euclidean view of downtown San Francisco.

The Ferry Building and palm trees along the Embarcadero illuminated in the late afternoon sun.

A statue of Mohandas Gandhi at the San Francisco ferry boat terminal.

Skyscrapers of downtown San Francisco.

A seagull taking in the view of the San Francisco-Oakland Bay Bridge.

Skyscrapers of downtown San Francisco as seen from the ferry boat terminal.

A sign on a construction site along the Embarcadero in San Francisco.

A container ship heads up the bay as framed between Tractor Tugs and bay tour boats.

The Golden Gate Bridge as seen over the wharves at Fort Mason.

The Golden Gate Bridge as seen over the wharves at Fort Mason.

Eucalyptus trees on a hillside at Fort Mason showing the effects of the prevailing wind direction.

Huge eucalyptus trees at Fort Mason.

Alcatraz Island framed between two cypress trees at Fort Mason.

The basin at the San Francisco Maritime National Historic Park. The old square- rigger BALCLUTHA is in the right-center of the photo.

A flower bedecked hillside adorns the entrance to Fort Mason, now part of the Golden Gate National Recreation Area. During World War II, Fort Mason served as the shipping point for 1.5 million troops who were shipped to Pacific war zones.

A great white shark image dominates a wall mural at the NOAA Gulf of the Farallons National Marine Sanctuary Headquarters.

The Golden Gate Bridge as seen from the NOAA Gulf of the Farallons National Marine Sanctuary Headquarters.

San Francisco skyline and the NOAA NOS Center for Operational Oceanographic Products tide house (small building to right on pier) as seen from the vicinity of the NOAA Gulf of the Farallons National Marine Sanctuary. The San Francisco tide gauge has produced the longest continual tidal record in the Americas. It began operation on June 30, 1854.

A ship passing under the Golden Gate Bridge.

A view of the Golden Gate Bridge as seen from the NOAA Gulf of the Farallons National Marine Sanctuary Headquarters.

San Francisco skyline as seen from Fort Point area.

Plaque commemorating 150 years of continuous tidal observations by the San Francisco tide gauge.

The San Francisco tide gauge house at the celebration of 150 years of continuous observations, the longest tidal record in the Americas. Alcatraz Island is to the right of the tide house.

A commemorative bench mark celebrating 150 years of continuous operations by the San Francisco tide gauge, the longest running series of tidal observations in the Americas.

A view of the square-rigger BALCLUTHA and Alcatraz Island from near the San Francisco Maritime Museum.

Vine with flowers hanging from tree on Daniel Island.

Sea turtle sculpture at Daniel Island Children's Park.

Sea turtle sculpture at Daniel Island Children's Park.

Salt water marsh, oaks and Spanish moss near the Wando River at Daniel Island.

A salt water marsh giving the appearance of a luxuriant meadow near the Wando River.

Spanish moss ( Tillandsia usneoides).

The edge of the salt marsh meeting oak and other higher ground flora on Daniel Island.

Oak, Spanish moss, and salt marsh on Daniel Island near the Wando River.

Wando River shoreline at low tide.

Look closely to see the fiddler crabs scurrying for cover in the marsh grass.

Look closely to see the fiddler crabs scurrying for cover in the marsh grass.

Looking across Wando River shoreline at low tide to the container terminal from Daniel Island.

Giant oaks on Daniel Island.

Giant oaks on Daniel Island.

Giant oaks on Daniel Island.

A plaque at Fort Moultrie commemorating the landing place of thousands of African-Americans on American soil and the subsequent achievements of the African-American community.

Pelicans and containership ship seen from near Fort Moultrie.