Katwijk: Mouth of the Rhein 
Description
In reality this is just the mouth of the Oude Rijn branch that runs through Leiden, and is today a small outlet under the control of sea defences and locks. Historically though this river marked part of the northern boundary of the Roman Empire so has been historically significant for a long time.
Charge
Free
Getting There
Bus Route 90 runs from Leiden Centraal Station and takes a more scenic route than the direct 431 but does serve the whole of the seafront at Katwijk, including stopping near the mouth of the Rhein. Buses run every hour and take about 30 minutes.Latitude: 52.210666; Longitude: 4.400823
What3Words: sailed.shelters.tone
