The highways of ancient greeks were actually sea-lands and navigational channels throughout the mediterranean sea. compare the advantages of movement by water for the greeks with movement by land for the romans

Greeks did not have such a large empire as the Romans did. For Greeks, naval journeys were of high importance because Greeks have a lot of islands, peninsulas, seas and rivers, and their journeys would be much faster if naval routes were used. Unlike them, Romans held almost what was the entire known world and many places were inaccessible other than by foot, especially northern parts or french ones when they fought gauls or german barbarians.