Atlas Quiz (Million Cities)

Map quizzes: Million Cities, Physical features (oceans, seas, rivers, lakes, mountains, deserts, islands …), Languages (where they're spoken, with hello / thank you / goodbye and pronunciation) and, per country, Austria (in German): the 200 largest Gemeinden (practise the top 100, ranks 101–200 or all 200) and Austria's rivers, lakes, glaciers, mountain groups, peaks, passes, valleys and gorges. Each has a type-in quiz, practice modes with an easier/harder setting and an atlas.

Million Cities

Learn all 511 cities in the world with more than one million inhabitants: a type-in quiz with a map, practice modes (name the city, find it on the map, which one is bigger?) and an atlas with every city's population, rank, growth from 1975 to 2050, and the towns it includes. A selector adds the 149 cities between 800,000 and 1 million (660 in total).

Three databases can be switched: agglomerations (UN WUP 2025, one method everywhere, the default), national definitions (UN WUP 2018, each country's own definition) and city proper (administrative city populations from Wikidata).

Play: https://squeakycamp.github.io/million-cities/

Progress is saved in your browser (localStorage).

Data

Quiz sets (see each quiz's “?” page):

• Physical features: Natural Earth 1:10m physical layers (public domain); selection, lengths/areas/heights and article links from Wikidata (CC0).
• Languages: areas built from Natural Earth country/state borders; areas, speaker estimates, phrases and facts compiled with Claude.
• Austria: population by Gemeinde and boundaries © Statistik Austria (CC BY 4.0). Physical features: rivers, lakes and glaciers © OpenStreetMap contributors (ODbL), mountain groups from the GMBA Mountain Inventory v2 (CC BY 4.0), points and figures from Wikidata.
• Facts in the info boxes were written with Claude from the English (for Austria the German) Wikipedia intros (CC BY-SA 4.0).

Million Cities:

• Cities and populations: United Nations, Department of Economic and Social Affairs, Population Division (2025). World Urbanization Prospects 2025, mid-2025 estimates of cities defined by the Degree of Urbanisation (contiguous 1 km² cells with ≥ 1,500 inhabitants/km² and ≥ 50,000 people). CC BY 3.0 IGO. https://population.un.org/wup/
• National definitions: UN DESA (2018), World Urbanization Prospects: The 2018 Revision, urban agglomerations ≥ 300,000 (projection for 2025). CC BY 3.0 IGO.
• City proper: Wikidata (CC0), filtered and cleaned (see tools/build_alt.py).
• City outlines: European Commission, JRC. GHSL Urban Centre Database R2024A. Where WUP splits one GHSL urban centre into several cities, the outline is divided so each city gets its WUP area (approximate).
• Alternative names and places inside each city: GeoNames, CC BY 4.0.
• City facts: short notes written with Claude from each city's English Wikipedia article intro (CC BY-SA 4.0); the info box links the article. Matching and texts: tools/fetch_wiki.py, tools/facts/.
• Borders, rivers, lakes: Natural Earth (public domain).
• Map tiles: terrain from AWS Terrain Tiles (Mapzen), physical and satellite maps © Esri.
• Map library: MapLibre GL JS (BSD-3-Clause), fonts: Noto Sans (OFL) via OpenFreeMap.

Running it yourself

python3 server.py serves static/ and stores progress on the server (data/state.json), so several devices can share one profile. Settings go in settings.local.json ({"host": "127.0.0.1", "port": 8170}).

To rebuild the data: tools/prepare_raw.sh (downloads the raw sources, ~700 MB) and then tools/build.sh. Requires pip install shapely pyproj openpyxl xlrd numpy. Name fixes and extra accepted answers are in tools/overrides.py.