A spectacular and colourful panorama of floats, immaculate marching contingents and dancing children unfolded before US President Barack Obama,who became the first American President to grace the Republic Day celebrations.Obama is also the first American President to visit India twice.Barack and Michelle Obama were received at the VVIP dais of the ceremonial boulevard Rajpath by Vice President Hamid Ansari and his wife Salma, Prime Minister Narendra Modi and Defence Minister Manohar Parrikar.As the nearly two-hour-long parade, showcasing the country's 'unity in diversity' marched down the Rajpath in drizzle and overcast skies, thousands of spectators gathered along the route and cheered in joy.