I find it fascinating to learn about wine history through maps. The devastation of Europe's vineyards by the louse Phylloxera, certainly changed the landscape of the regions and the migration of vineyard workers. It was also a turning point in the most important wine-producing regions of the world, leading to the reorganization of vineyards, grapes planted, opportunities for acquisition of land and the extinction of many of the lesser known grapes.
Phylloxera is a bug. A bad, bad, very bad bug. Its tiny and indigenous to North America, and likes to feed on the roots of grapevines. You can certainly read more about it here, or purchase one of my favorite books: Phylloxera: How Wine was Saved for the World by Christy Cambell.
This is a compilation of maps created between 1870-1909 that show the spread of the bug Phylloxera through parts of Europe.
Spain (Rioja) 1901
New Zealand 1885
South Africa 1885