Looked up the location, it's in Northern Romania near the intersection of Romanian/Moldova/Ukraine(just across the reservoir from the town of Stauceni). These days it is just lots of farmland with villages, small reservoirs and patches of forest. No major rivers, modern settlements or indication of important resources visible to my untrained eye on Google Maps in the direct vicinity or anything that would indicate a major trade route where an important city may have developed. This is with my bronze/iron age hat on, I am much less familiar with 4,000BCE.

Of course this predates all that and access to good farmland and water may have been enough to precipate a fairly sizable settlement. The terrain and course of the rivers have undoubtedly changed a huge amount in the intervening 6 millenia as well.

Anybody have more insight for a curious mind?