President Pranab Mukherjee led the nation in paying homage to former Prime Minister Rajiv Gandhi on his 71st birth anniversary on Thursday. Congress President and Rajiv Gandhi's wife Sonia Gandhi, son Rahul Gandhi, daughter Priyanka Gandhi, son-in-law Robert Vadra and granddaughter Miraya Vadra paid tribute at his memorial, Vir Bhumi, in New Delhi. Vice-President Hamid Ansari and former Prime Minister Manmohan Singh also paid homage to Rajiv Gandhi. Birth anniversary of Rajiv Gandhi is observed as Sadbhavna Diwas (harmony day) in the country. Rajiv Gandhi became the youngest PM of the country when he took office after his mother Indira Gandhi's assassination on October 31, 1984. Rajiv was killed by an ethnic Tamil suicide bomber while campaigning in an election in the south Indian town of Sriperumbudur in May 1991.