Catherine the Great filmed at Trakai Island Castle, Trakai. An island castle in Lithuania that was one of the production's stops across Europe.
Probable Named in published production coverage; the coordinate is the place itself, checked against a gazetteer.
Venture keeps every scene location on one map, sorted by how far you'd have to walk. Open it in Trakai and it tells you what was shot around you, how to get there, and whether you can actually go in.
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