IsaacAsimov/TrantoR

The planet /TrantoR was the capital of the /FirstGalacticEmpire?. Its land surface of 200 million sq. km. was -- with exception of the Imperial Palace area -- entirely domed. It consisted of an enourmous MegalopoliS? that stretched deep underground and was a home to 40,000,000,000 (40 bil.) inhabitants.