The extensive Roman road system helped early Christians to spread the good news throughout the empire. The apostle Paul no doubt traveled many miles on these roads. (Col 1:23) The diagram shown here illustrates the typical construction of a stone-paved Roman road. First, the path was marked. Next, builders dug a trench for the road and filled the trench with layers of road base made of stones, cement, and sand. The workers paved the road with large stone slabs and installed curb stones that helped keep the paving in place. The materials used and the camber of the road allowed water to drain from its surface. Outlets placed at intervals along the curbs let water escape into ditches that ran beside the road. The builders did such excellent work that some of their roads are still in existence today. Most roads in the Roman Empire, however, were not this sophisticated. The most common types were made simply of packed gravel.