The busiest unit in our national park system isn't a park at all. In fact, plenty of visitors never notice that they're in it — not when they're half-lost in the redwoods of Marin County's Muir Woods, not when they're deep into a conversation about robots at San Francisco's Ft. Mason, not when they're roaming the vast beach flats of Ft. Funston, near the San Mateo County line.

Peering through binoculars, a flock of volunteer raptor watchers perched high in the Marin Headlands reacts excitedly to a pair of peregrine falcons swooping through the Golden Gate.

The best view of the Marin Headlands may be from across the Golden Gate at Battery East, which was revamped and unveiled to the public this week.

Six-week program for Linking Individuals to their Natural Environment (LINC) in Marin, a summer internship for high school students run by the Golden Gate National Parks Conservancy. where students help with service projects, gain career and leadership skills and take work trips to park sites.

After being jailed by the Chinese government in 2011, and his work censored in the country, the dissident artist Ai Weiwei received his passport back this week.