Merradalsbekken is the shortest of Oslo's rivers. It is approx. 5 km long and runs from Voksenåsen/Holmenkollen to Bestumkilen at Skøyen. Parts of the river are laid in a culvert, but in a stretch of 2 km from Sørkedalsveien to Ullernchausseen it runs through Merradalen, which is a narrow valley with great biodiversity. Here there are many different plants, forests with several types of trees and a hiking trail that follows the river. This article describes the hike along the