Unknown Horizons

Unknown Horizons is a free, open source economy and city-building simulation that takes its cues from the classic Anno series, particularly Anno 1602, without being a direct clone. The Unknown Horizons Developers built it from scratch in Python using the FIFE isometric engine, with their own original artwork and a supply-chain-heavy economic model that goes well beyond simple zone placement. You start with a ship and a group of settlers on a newly discovered archipelago, claim an island, and build from there, managing resources, production chains, trade routes, and population needs across multiple islands.

The game sits in a particular niche on this list: it’s the only pick that leans more toward the Anno end of the city-builder spectrum than the SimCity end, with an emphasis on goods production, inter-island trade, diplomacy, and competing colonies rather than urban zoning and traffic management. Development effectively stopped with the 2019.1 release, and a planned Godot engine port is in progress but has no playable build yet. The legacy version is fully playable on Windows and Linux right now. Curious where it ranks alongside the other options? See the full best free city building simulation games list for comparison.

Is Unknown Horizons Free?

Yes, Unknown Horizons is completely free and open source. The source code is released under the GPL v2 and the game content is mostly licensed under CC-BY-SA. There is no cost to download or play, no ads, and no paid edition. The project accepts no monetisation of any kind.

Gameplay & Features

The core loop revolves around supply chains rather than zoning. Settlers need food, tools, and eventually cloth, tobacco, and other goods as they advance through social classes. Each good requires a production building, often several in sequence: growing grain leads to a mill which leads to a bakery before bread reaches your population. Keeping those chains funded, stocked, and connected to the right residents is what the game is actually about, with city-building as the visible result of that economic juggling act.

• Six settler class levels. Pioneers advance to Sailors, then Settlers, Citizens, Merchants, and finally Aristocrats. Each step up unlocks new buildings and opens new production chains, but also raises the goods those residents demand. Getting ahead of their needs is the central challenge.
• Multi-island archipelago maps. Islands have different resource deposits, so no single island can be fully self-sufficient. Sending trade ships between your own settlements, or trading with AI colonies and neutral traders, is part of the expected loop rather than an optional extra.
• Diplomacy and trade agreements. Negotiate non-aggression pacts, set trading conditions with other factions, and build relationships with indigenous settlements on the map. Going to war for territory is also an option.
• Multiplayer. Local and online multiplayer is supported in the legacy 2019.1 build via pynet, one of the few free city builders on this list that supports co-op or competitive play.
• Scenario editor. The game ships with a map and scenario editor, allowing custom campaigns and hand-crafted island layouts to be created and shared.

Players who want a more traditional SimCity-style experience should start with LinCity-NG or TheoTown instead. Unknown Horizons rewards players who enjoy the economic puzzle of Anno-style games: production chains, trade logistics, and population happiness through goods supply rather than urban zoning. If the vertical colony angle sounds more interesting, The Final Earth 2 is the sharpest contrast in the set, while Micropolis offers the genre’s purest historical roots and Cytopia the most visually polished open source building sandbox.

PC System Requirements

Unknown Horizons has no formally published hardware requirements. It runs comfortably on modest hardware given its Python and SDL2 foundation. Windows and Linux are supported for the current 2019.1 release. Mac users can run an older 2014.1 build, but it is significantly out of date.

How to Download & Play Unknown Horizons for Free

Unknown Horizons is available from the official project website. No account is required.

1. Windows installer. Download the 2019.1 Windows installer directly from the official Unknown Horizons downloads page, an official, safe source. The installer includes all dependencies including Python. Download size is approximately 145 MB. Run the installer and launch from the desktop shortcut.
2. Linux. A source tarball for 2019.1 is available from the same downloads page. Most major distributions also carry Unknown Horizons in their package repositories; search for unknown-horizons in your package manager. Dependencies include Python 3, python3-fife, and python3-yaml.
3. Mac. No current Mac build is available. The last compiled macOS version is 2014.1, which is significantly out of date. Mac users can attempt to build from source via the GitHub repository, but this is not straightforward.

FAQ

Is Unknown Horizons still being developed? Actively maintained development stopped around 2019. A Godot engine port is in progress and listed on the official site, but as of late 2026 no playable build of the Godot version is available. The 2019.1 FIFE legacy build remains the current playable release.

Is it really like Anno? Inspired by, not a clone of Anno 1602. The island-hopping, supply chain production, and social class progression come from the same design tradition, but the art, engine, and maps are all original. Players familiar with Anno 1602 or Anno 1503 will find the loop immediately recognisable.

Does multiplayer work? Multiplayer is supported in the 2019.1 build via the optional pynet library. The online matchmaking infrastructure is no longer officially maintained, so multiplayer is best set up via direct IP connection with friends.

Can I make my own maps? Yes. A scenario and map editor is included in the game. Custom maps can be saved and shared as files.