Oste Barrier at the Mouth of the Oste River

You cannot cross the Oste by bike closer to the Elbe. You should definitely pay attention to the opening times, otherwise the detour is not negligible.
April 1st to September 30th
Tuesday to Thursday from 10 a.m. to 5 p.m.
Sat + Sun from 10 a.m. to 6 p.m.
October 1st to March 31st
Tuesday to Thursday from 10 a.m. to 5 p.m.
Sat + Sun from 10 a.m. to 5 p.m.

Bridge closing times
The bridge is open by default. Closing times can be found at wsa-cuxhaven.de

How do I find an impressive structure!
Wikipedia says;
In October 1964, construction began east of the natural Ostelaufes in the district Balje, districts Hörne and Neuhaus, near the mouth of the Elbe by digging a large open pit, which was kept dry by lowering the groundwater by 101 wells with associated pumps. This huge pit was protected by new dykes against possible storm surges, a large transshipment point for gravel and other building materials was on the old arm of the Oste, in today's Baltic Sea - on the sheet pile still visible - built. In the spring of 1966 all preliminary work was completed and concrete work could begin. Here, a part of the sole was poured with the associated concrete pier in one step. A total of 20,000 m³ of concrete was processed. The entire concrete body is framed by a steel sheet piling and with casement walls by a steel tension pile anchorage
de.wikipedia.org/wiki/Ostesperrwerk