There are also some units that exist in space exclusively (i.e. While the Swarm warrior can survive in space as well as the earth, it cannot launch itself into space. Space Fighters and Space Planes can freely travel in space and in the atmosphere. All land and naval units are exclusively terrestrial, although most land units can be launched into space inside a Cargo Pod by a Rail Launcher in cities or via a Space Plane. Players can toggle between 'Earth view' and 'space view'. Similar to Civilization II, the game uses an isometric view, although each tile is actually two separate tiles: the space level on top of a 'terrestrial' level (thus, this game has a z-coordinate to represent position). In the game, space colonization and sea colonization become a reality with appropriate technological advances (available in the Genetic Age). There are five epochs in this game: Ancient Age, Renaissance, Modern Age, Genetic Age, and Diamond Age. One of the most noticeable differences from the original Civilization is that the timeline of the game does not end in the 21st century, but rather goes to the year 3000.