Cyrus the Great's Royal Road

The Achaemenids were the founding dynasty of the Persian Empire. Led by Cyrus the Great and his grandson Darius, they annexed most of Anatolia, and their empire eventually included Libya, Ethiopia, Thrace, Macedonia, Afghanistan, and the Punjab and everything in between. One of their achievements was to construct a 1500 mile road (probably following an older military track, or parts of it) between Susa in Iraq and the Aegean Coast.

You should really read more about it, to get a good idea:

• The Royal Road of the Achaemenid Dynasty
• The Achaemenid Dynasty
• The Persian Empire Timeline and Description