Kos Minars are solid round pillars, around 30 feet (9.1 m) in height, on a masonry platform built with bricks and plastered over with lime.
In the third century BC, emperor Ashoka improved existing routes linking his capital city Pataliputra to Dhaka in the east and Kabul via Peshawar in the west and further to Balkh.
These routes had landmarks in the form of mud pillars, trees or wells to guide commuters.
[4] The 16th-century Pashtun ruler Sher Shah Suri introduced improved brick pillars plastered over with lime at every kos.
[4] The Archaeological Survey of India has given Kos Minars protected status and courts have ordered encroachments cleared away.