Prime Minister Narendra Modi on Tuesday laid a wreath at the Tomb of Unknown Soldiers and paid homage to Indian-American astronaut late Kalpana Chawla at Arlington National Cemetery here.”Honouring sacrifice, saluting valour. Formal engagements begin with a solemn ceremony,” External Affairs Ministry spokesperson Vikas Swarup tweeted.”In homage to heroism and indomitable courage,” Swarup said in another tweet.<!– /11440465/Dna_Article_Middle_300x250_BTF –>He also had a brief interaction with the husband and family members of Chawla, senior officials from NASA, Indian-American astronaut Sunita Williams and her father at Space Shuttle Columbia Memorial.US Defense Secretary Ashton Carter accompanied the Prime Minister. Indian Ambassador to the US Arun K Singh, Foreign Secretary S Jaishankar, US Ambassador to India Richard Verma and Assistant Secretary of State for South and Central Asia Nisha Desai Biswal were also present on the occasion.Modi also thanked the US for returning over 200 cultural artifacts estimated at US $100 million to India at a ceremony here attended by Prime Minister Narendra Modi.”A focus on heritage & culture…I thank the US government for the return of precious cultural artefacts to India,” PM said at the ceremony held at the Blair House.”For some, these artifacts may be measured in monetary terms but for us this is beyond that. It’s a part of our culture and heritage,” he added.Items returned included religious statues, bronzes and terra cotta pieces, some dating back 2,000 years, looted from some of India’s most treasured religious sites.Modi also interacted with heads of the United States’ think tanks. Indian Ambassador to the US Arun Kumar Singh said the aim of the interaction was to understand from them how they see the global trends in the coming years.”The aim of the interaction was to understand from them how they see the global trends in the coming years, the challenges and what the US and India could work together, keeping in mind the templates that the Prime Minister has articulated is what can the US and India do together for the world and that was really the theme,” said Singh.Divulging details about the think tanks, he said they were from Brookings, Council on Foreign Relations, Centre for American Progress, the Atlantic Council, Houston Institute, Central for National Interest, Global Energy Capital, Carnegie Endowment, the Asia Group, Pew Research Centre, the US Institute of Peace and the Foundation for Defence of Democracies.”So, this is sort of think tanks representing whole spectrum of opinion here,” said Singh, adding, “So, it was in that framework that different current global issues were in a medium and longer term perspective, and we looked at opportunities and ways for us to be able to work together.”On June 8 (Wednesday), the forenoon is devoted to events in the US Congress.He would be going to the US Congress, meeting the Speaker, the Congressional leadership. And he would be delivering an address to the joint meeting of the US Congress. This would be followed by a lunch, which is hosted by the Speaker in honour of the Prime Minister, followed by a reception, which will be jointly done by the House and Senate Committees on Foreign Relations and the India Caucus and a brief community reception.