How was the Harappan Civilisation discovered? Name the two archaeologists associated with this discovery.

In 1920, during the construction of a railway track near Harappa, the railway authorities noticed that the bricks which were used from a nearby ruin belonged to a very old Civilisation. The Archaeological survey of India working on this information carried out extensive excavations at the site which lead to the discovery of the Harappan Civilisation. The two archaeologists associated with this discovery are Dayaram Sahni and R.D. Banerjee.