Golden Gate Park is one of the largest urban parks in the world, covering over 1,000 acres. Start your day with a walk or bike ride through the park to get your blood pumping. You'll see beautiful gardens, a Japanese tea garden, a botanical garden, and more. Don't miss the de Young Museum, where you can see art from around the world, or the California Academy of Sciences, which has a planetarium, an aquarium, and a natural history museum. End your day with a picnic by Stow Lake.
Take an early ferry to Alcatraz Island, a former federal prison that housed some of the country's most notorious criminals. The audio tour provides a fascinating look into the lives of the prisoners and guards who lived on the island. After returning to the mainland, head to Crissy Field to take a walk along the beach and soak up views of the Golden Gate Bridge. End your day with an adrenaline-filled bike ride down Lombard Street, the "crookedest street in the world."
If you have more time, consider a day trip to wine country or a visit to the Muir Woods National Monument. If you have less time, skip the California Academy of Sciences and go straight to the Golden Gate Park. You can also substitute a hike in Lands End or a visit to the Cable Car Museum for the bike ride down Lombard Street.