Tiberium

Tiberium was the capital world of The United Ecumene. It was the third planet in the binary star system Primus and the most densely populated.

Topography
Tiberium was approximately 400 million years older than Earth and about 4,000 kilometers bigger in diameter, also making it the second largest planet in the Primus system next to Pertinax. A city of the same name spanned across all of its land masses, along with several underwater bases and the floating suburb of Panganoda.

Flora and Fauna
In the beginning Tiberium was a harsh and heavily forested and rocky planet with thousands of different species of trees, plants, and animals. It was terraformed by an unknown humanoid species thousands of years before the arrival of humans and shortly after the creation of the Ecumene. The originating species left abruptly sometime after they finished, taking with them much of the original vegetation.