California's oldest zoo, open since 1907, sits inside Sequoia Park at 3414 W Street — a city park anchored by a small stand of old-growth coastal redwoods. The zoo is small and free, with a focus on native California species alongside the usual mix of primates and birds. The redwood grove alone is worth the visit; these are among the few old-growth trees remaining within the city limits, spared when the rest of the surrounding forest was logged.
The park itself is a pleasant place to walk on a foggy Eureka afternoon: open lawns, a duck pond, and the cool quiet of trees that were already centuries old when the first settlers arrived. Free admission.