2K and Firaxis Games on Monday announced the first expansion for Civilization: Beyond Earth. Called Rising Tide, the $30 expansion adds new biomes, introduces more diplomatic options, welcomes new factions, and more. The add-on launches this fall for PC and you can read our new preview right here.

As its name suggests, Rising Tide lets players colonize the ocean, while introducing new aquatic gameplay and alien beasts to take on. 2K and Firaxis also promise an "overhauled diplomacy system," while a new Artifact System will allow players to collect and combine alien relics.

One of the new factions is the Al Falah, which Firaxis describes as a "group of nomad explorers descended from wealthy and resilient Middle Eastern states." Another new system will allow players to invest in multiple Affinities as part of their effort to unlock hybrid Affinity units, a first for the series.

As for the worlds players will explore, one is the Primordial world. Firaxis describes this place as an "untamed biome rife with volcanic activity and indicative of a chaotic landscape still forming in the new world."

"It's not just moving things out to the water; it's not just blue terrain," co-lead designer David McDonough told GameSpot about Rising Tide's new gameplay features. "We really changed some of the very fundamental ways in which you build cities, capture territory, develop, and grow, so that if you play at sea, you have a whole different strategic landscape."

Rising Tide is also coming to Mac and Linux, by way of ports from Aspyr. For lots more on Rising Tide, check out GameSpot's new preview and some images in the gallery below.