Outerra is a brand new engine.. currently in development.. this engine is optimized to rendering entire planets!

Visit the Official Site

The demo comes with the whole planet Earth that can be explored in a free-camera mode or in a 8-wheeler truck. People who like it and/or want to support the authors and the development of Outerra engine can buy the alpha release of Anteworld (the game that uses the engine) at a discounted price ($15), half the amount for the final release. Doing so will give you access to regularly released alpha/beta updates of the game, together with the final version when it’s done. The price will gradually rise with each major release.

Please note that the tech demo is in alpha state, which means it lacks many features and special effects.