Natural Earth
Natural Earth is a curated set of map data built to make good-looking maps at small and medium scales, and it comes at three levels of detail labelled by map scale: 1:10m (the most detailed), 1:50m, and 1:110m (the coarsest, good for whole-world views). Rather than chasing exhaustive coverage, it offers clean, consistent features that render well, which is why newsrooms, atlases, and data visualisations reach for it. The cultural themes cover country and state boundaries, populated places, roads, railways, and airports; the physical themes cover coastlines, rivers, lakes, glaciers, and bathymetry (undersea depth).
Everything is a plain download from the site, theme by theme or as bundled packages, with no account needed. Vector data ships as shapefiles (a common GIS format of points, lines, and polygons) and raster imagery as GeoTIFF. For a RAG system you will usually want the attribute tables rather than the geometry: each place or boundary carries fields such as its name, country, and population, which you can flatten into short text records ("Lyon is a city in France") and embed for retrieval. Tools like GeoPandas or ogr2ogr will read the shapefiles and let you dump those attributes to CSV or JSON in a few lines.
Natural Earth is best when you need a light, dependable gazetteer of administrative areas and place names and you do not need street-level precision. It suits a geography-aware assistant, a tool that resolves a place mention to a country or region, or a way to hand a model a clean list of the world's nations and capitals.
The data is public domain with no attribution required, so commercial use is unrestricted and you can redistribute derived text freely. The main caveat is detail: it deliberately omits small features, so it is the wrong choice for local mapping. When you need that, OpenStreetMap goes far deeper and GeoNames offers a larger flat catalogue of place names; Natural Earth is the tidy, low-effort baseline alongside them.
Related sources
GeoNames
A geographical database of more than 11 million place names, each with coordinates, population, elevation, and administrative divisions, covering every country. It works well as a gazetteer for resolving place names to locations.
Google-Microsoft-OSM Open Buildings (VIDA)
A conflated global building-footprint layer that merges Google Open Buildings V3, Microsoft Global ML Footprints, and OpenStreetMap into roughly 2.7 billion footprints, each labelled by its source. Built by VIDA and hosted on Source Cooperative in cloud-native formats, it offers more complete coverage than any single provider on its own.
OpenStreetMap
A crowdsourced map of the world, built and maintained by a community of volunteers. It holds detailed geographic data on roads, buildings, land use, points of interest, and much more, which you can download as a full planet file or as smaller regional extracts.
Overture Maps Foundation
An open map data project run under the Linux Foundation by a group of industry members. It combines and harmonises data from OpenStreetMap, Microsoft, Meta, and others into consistent, interoperable map layers you can build on freely.