Osowiec-Twierdza Boardwalk

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Part of the 9km of walking paths near the visitor centre, this 1km-long boardwalk has sweeping views of the sea of reeds across the marshes and the Biebrza River, especially from the wooden observation tower. It's about 2km northwest of the visitor centre; the path linking the two crosses the river, where there are more good views. Don't miss the moody ruins of the sprawling 19th-century concrete fortifications built by Tsar Alexander III to protect this strategic narrow river crossing.

The west end of the boardwalk can be accessed from a point near where Hwy 65 crosses the river.