Explanation: first visited by Charles Mason in 1826, and Amri by Alexander Burnes in 1831. The site of Harappa was destroyed for laying the railway line from Lahore to Multan.

• The seal from this site reached Alexander Cunningham, the first surveyor of the Archaeological Survey of India (ASI). Alexander Cunningham visited the site in 1853, 1856 and 1875.
• But the importance of the site and the associated civilization were not realized until Sir John Marshal took over as the Director General of ASI and initiated research at the site.

Source: Tamil Nadu NCERT