Which technological helped unify both the Roman andt Inca Empires?

Both the Roman and Inca Empires were significantly unified by their extensive road systems. The Romans built a vast network of roads that facilitated trade, military movement, and communication across their empire, promoting integration and control. Similarly, the Incas developed an impressive system of roads and bridges across the Andes, which enabled them to manage their vast territory efficiently and connect diverse populations. This infrastructure was crucial for governance and cultural exchange in both empires.