Borderline
Five old political maps with the date torn off. Each shows only borders and country names. Work out when it was printed: a Russian Alaska, a Persia not yet called Iran, an Austria-Hungary still in one piece. Every map fits a window of years. A guess inside it scores 5,000; the further outside, the fewer points.
When is this map from?
Drag the slider or type a year, then lock it in.
The tells
Your score
| Map | Window | Guess | Points |
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About Borderline
The idea came from a map in an IB Theory of Knowledge classroom that still shows Russian Alaska. We tried to date it from its borders and names alone.
Every map is drawn in the same old-atlas style whatever its year, so the style never gives the date away. A map fits a window of years: from the latest change among the things on it to the day before the next change. A border change counts only if it would be visible on a phone, a patch of at least 120 square pixels that is more than two pixels thick; a rename counts if the country is labeled. The two changes that set the window are the tells.
Borders follow the CShapes 2.0 dataset. Where territory is disputed, the map shows that dataset's coding, which is not a position on sovereignty.
Data
- CShapes 2.0 (1886 to 2019), by Guy Schvitz, Seraina Rüegger, Luc Girardin, Lars-Erik Cederman, Nils Weidmann and Kristian Skrede Gleditsch, ETH Zürich, from the cshapes R package. Licensed CC BY-NC-SA 4.0; the map files made from it here are shared under the same license.
- CShapes-Europe (1816 to 1885), by Lars-Erik Cederman, Luc Girardin, Carl Müller-Crepon and Yannick Pengl, from Nationalism and the Transformation of the State (Cambridge University Press, 2025). Licensed CC BY-NC-SA 4.0. Its records are the borders of 1 January each year, so each change used as a tell here carries its real date from a cited source.
- historical-basemaps by André Ourednik, for the hand-picked maps before 1886 outside Europe. Licensed GPL-3.0; the map files made from it here are shared under the same license. Its snapshots mix borders from different years, so each crop was checked by hand and dated from the cited facts it shows.
- Country names, renames, the dates CShapes-Europe leaves out, and the hand-picked maps are in the data folder, each date with its source.