Quarantine wall appeared in Odessa in early 19th century. It protected the city from the plague, separating newcoming ships from the main city. Then they stood idle for several weeks in quarantine to prevent the spread of the epidemic of plague in Odessa. The tower is used to store gunpowder, which were removed from the ships. Now they are in Shevchenko park.
 

The cache on map is not at given coordinates. You need to decrypt below map code to get correct location on the map.

0VG.3X

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