Sher Shah Suri ruled northern India for five years after driving Humayun out, and in that time rebuilt the road from Bengal to the Indus, the Sadak-e-Azam, which the British later called the Grand Trunk Road.
He planted trees along it, sank wells, and built serais at intervals with separate quarters, a well and a mosque, and posted a runner service that could carry news the length of it in days.
He built Rohtas fort in Jhelum district to hold the Punjab against the Gakhars and against Humayun's return. It is four kilometres of wall and was never taken.
He reformed the revenue system on measurement and standardised the silver rupee, which is the direct ancestor of the currency of India, Pakistan and several other countries.
Five years of an Afghan usurper's rule produced the road, the currency and the revenue system that the Mughals then used for two hundred years and the British after them.
The Punjab stretch of that road is still the main highway and the serais at Doraha, Dakhni and Phillaur are on it.
The road ran from Sonargaon in Bengal to Kabul, rebuilt and provisioned under Sher Shah Suri in the 1540s with serais, wells, shade trees and a post service.
Its Punjab section is the spine of the province: Delhi, Karnal, Ambala, Sirhind, Ludhiana, Jalandhar, Amritsar, Lahore, Rawalpindi, Attock.
Every subsequent power used it. The Mughals extended the serais, the British put the railway alongside it, and the modern highway follows the same line.