Without a doubt, Castalia Provincial Park is one of the island's most diverse and intriguing landscapes. At high tide, you drive out on a thin spit of land between what appears to be two arms of the sea. At low tide, however, the park's fascinating diversity reveals itself: an inland salt marsh, rushing streams, fertile fields, sand dunes, rocky beaches, sand beaches and enormous tidal flats.
At several points along the drive, there are covered picnic areas with barbeques - and a great view of the water fowl which flock to the area to feed at low tide - both Grand Manan native birds and a wide variety of feathered visitors.
The park also features walking paths along the top of the dunes and reveal the other great diversity of the landscape: wild flowers - in a very small area, everything from the marsh plants, those which prefer the tops of the sand dunes, and the ones which prefer the sea spray. Somewhat defying logic, one of the most prolific plants is Grand Manan's famous wild roses, including the rarer white variety.
But don't forget to stop and smell the thistles! (a piece of advice I picked up from Wendy Dathan at one of the Grand Manan Museum's evening talks on local flora.) Truly a surprise for a plant with such an otherwise prickly demeanor.
You can find a wide variety of shells, rocks and other beachcombing finds on the long stretch of gravel and sand beach. You can also great a great look at Long Island and the many fishing and sailing boats which pass by the area.