These buildings were originally a station of the U. S. Life-Saving Service. In 1890, they overlooked one of the world's busiest ports. When a ship was disabled or wrecked in the swift currents of San Francisco Bay, lifeboats were launched from the building with the watchtower. A dozen shipwrecks still lie beneath the waters around the Presidio.
In 1915, the Life-Saving Service merged with the Revenue Cutter Service to become the U. S. Coast Guard. Today these buildings are home to the visitor center for the Greater Farallones National Marine Sanctuary.
For me they are a reminder of how beautiful buildings are when their design is dictated by their purpose and when they employ passive lighting and ventilation systems (windows).
As for the palm trees, remember: there are no native trees in San Francisco.