Demerara River, Guyana

Where: Guianas · South America · approx. 6.8, -58.16 (vicinity only)

Why this spot: Dutch-then-British plantation colony - the trade's 'Demerara onions' come from this mud

What turns up: Dutch onion bottles, early English wines, case gin - the oldest glass on this map.

Access: Gray area.

Murky colonial-heritage legality; go with local fixers, expect export friction.

Satellite view, historic-map overlays, tide/flow context and field notes are in the app. Exact research detail is part of Pro.