Cul-de-sac is a word used for streets with entry only in one end. It is a French word, but is used in many languages.
Cul-de-sac is also a film from 1966 by the Polish-French director Roman Polanski (born in Paris 1933). The film tells the story of two gangsters who arrive at a remote castle to hide from the police. They take the couple who own the castle as hostage. It is a combination of black comedy and psychological thriller.
The film takes place at the island of Lindisfarne in northern England. The woman at the castle is played by Françoise Dorléac who might have become as famous as her sister Catherine Deneuve had she not been killed in a car crash in 1967.
Hopefully there are no gangsters around this cache, but it certainly is a cul-de-sac. Enjoy a nice walk or bike tour along the Baneasa lake, a part of the river Colentina. Please note that even though it might look that way on many maps, it is not possible to reach the cache from other directions than along the lakeside from the east.