When the tide goes out on Cape Cod Bay, the flats – basically giant sandbars – offer opportunities to commune with crabs, clams and gulls, and to take in brilliant sunsets. Best access to the tidal flats is via the Point of Rocks or Ellis Landing Beaches. Parking permits are required during summer (mid-June to early September) and cost $20 per day; they're available at the Brewster Chamber of Commerce.