The Grand Trunk Road in South Asia was the main road from modern day Bangladesh to northern Pakistan and Afghanistan. A route since antiquity, it was constructed into a coherent highway by the Maurya Empire in 300BC. Soon after, the Greek diplomat Megasthenes (c. 350 - c. 290 BC) wrote of his travels along the road to reach Hindu kingdoms in the 3rd century BC. After invading India over 1,500 years later, Mughals extended the Grand Trunk Road westwards from Lahore to Kabul (the capital of Afghanistan) crossing the Khyber Pass. The road was later improved and extended from Calcutta to Peshawar by the British rulers of colonial India. For many centuries, the road has acted as a major trade route and facilitated travel and postal communication. The Grand Trunk Road remains under use for transportation in India. The Khyber Pass was an all-season mountain pass connecting Afghanistan to western Pakistan.