Final answer:
Other than roads, the Inca built bridges and relay stations to improve travel and communication across their empire. These structures facilitated the movement of goods, armies, and chasquis, enabling the Inca to maintain a well-connected and cohesive empire.
Step-by-step explanation:
The Inca Empire was known for its advanced engineering which greatly contributed to its efficient travel and administration despite the challenging Andean terrain. Other than roads, they constructed an impressive network of bridges and relay stations to facilitate movement and communication across their vast domains. These rope, stone, and wood bridges spanned canyons and rivers, making the otherwise impassable landscapes navigable. Alongside the bridges, at regular intervals, were relay stations that played a critical role in the empire's logistics, functioning as hubs for rest, resupply, and the dispatch of the chasquis – the Incan relay runners. This network not only supported military and administrative movements but also helped in the transportation of goods and in maintaining a cohesive empire.