Traders & Barbarians is distributed as the third major expansion for The Settlers of Catan, although it is actually a compilation of small expansions and variants. (It is independent of the Seafarers and Cities & Knights expansions, but can be combined with them.)
A game of Via Nebula starts with a board showing a hexagonal grid, some production sites with a few available resources on them (wood, stone, wheat, and pigs), building sites in various areas scattered over the whole board, and a lot of mist.
Turn after turn, players have two actions at their disposal from these options: They may clear the mist of a hex to create new paths of transportation, open new production sites, open a building site in a city, carry resources from any production site to their own building sites, and, of course, achieve a construction. Resources and paths through the mist may be used by all the players. This initially induces a kind of cooperation, but eventually other players will take advantage of your actions!
