The structure of the memorial complex includes a museum, an open air exhibition of military equipment, coastal defense battery, a large park planted with oak trees. Visiting the tour, you will see in the park around the museum reconstructed line of defense with trenches and firing positions of artillery and mortar batteries.
The container is 20x10x7cm metal tea box. Many items, logbook and pencil are inclded :)
It's hidden in the slit under the main artillery gun of the exposition. Hint is more detailed if needed.