The Tiber River and Mediterranean Sea were major geographical features for Ancient Rome. Rome was situated on seven hills including the Aventine and Capitoline hills. Spain was Rome's western border while the Sahara Desert marked the southern edge. The Roman Empire also bordered Gaul, Carthage, and the Rhine and Danube Rivers. Etruscans believed gods communicated through nature for divination. Christians were buried in catacombs and believed in life after death. Romans practiced cremation and animal sacrifice in their religion. Early Roman law was publicly displayed to govern citizens. The Roman army and skilled artisans helped Rome achieve military and artistic successes.