The Briesetal is a small valley formed by the Briese river, very close to Berlin. It is a quiet nature preservation area, home to beavers whose dams created a sunken birch forest. It's the perfect getaway from the city's hustling without the need for long travel.
The path takes you up along the Briese, visiting several dams and the sunken forest, with a chance to see beavers at dawn or dusk. There's a small beer takeout at the apex, before you return along the opposite bank.