The Arcata Marsh and Wildlife Sanctuary is a thought-provoking excursion. The 154-acre sanctuary -- which doubles as Arcata’s integrated wetland wastewater treatment plant -- is a stopover for marsh wrens, egrets, and other waterfowl, including the rare Arctic loon. Every Saturday at 8:30am and 2pm, free 1-hour guided tours start at the cul-de-sac at the foot of South I Street. Or just pick up a free self-guided walking tour map of the preserve, available at the Arcata Chamber of Commerce, 1635 Heindon Rd. (707/822-3619; www.arcatachamber.com). Locals are proud of their town’s wastewater solution, boasting “Arcata Residents Flush with Pride.”