In Pics: Best photos from Donald Trump's inauguration day

Trump, 70, took the oath of office in front of about 800,000 people who braved chilly weather to gather on the National Mall in the center of the capital.

Washington, Jan 21: Donald Trump on Friday sworn-in as the 45th US President, taking over the reins from Barack Obama amid expectations of radical change in policies and apprehension at home and abroad.

Trump, 70, took the oath of office in front of about 800,000 people who braved chilly weather to gather on the National Mall in the center of the capital to celebrate the rank political outsider, who defied all odds to defeat political heavyweight Hillary Clinton in the November polls.

Donald Trump greets Barack Obama:

U.S. President-elect Donald Trump greets outgoing President Barack Obama before Trump is inaugurated during ceremonies on the Capitol in Washington, Jan. 20, 2017

The Obamas departure:

President Donald Trump and first lady Melania Trump talk with former President Barack Obama and Michelle Obama during a departure ceremony on the East Front of the U.S. Capitol in Washington.PTI

As Donald Trump waits to step out:

President-elect Donald Trump waits to step out onto the portico for his Presidential Inauguration at the U.S. Capitol in Washington.PTI

Swearing-in Ceremony of the 45th US President:

Donald Trump is sworn in as the 45th president of the United States by Chief Justice John Roberts as Melania Trump and his family looks on during the 58th Presidential Inauguration.PTI

Trump before Presidential inauguration:

President-elect Donald Trump pumps his fist as he arrives for his Presidential Inauguration at the U.S. Capitol in Washington.PTI

Donald trump inaugural address:

President Donald Trump delivers his inaugural address after being sworn in as the 45th president of the United States during the 58th Presidential Inauguration at the U.S. Capitol in Washington.PTI

Donald Trump signs first bill and actions as president:

President Donald Trump is joined by the Congressional leadership and his family as he formally signs his cabinet nominations into law, in the President's Room of the Senate, at the Capitol in Washington. PTI

Hundreds boo President Trump's motorcade:

The Presidential motorcade drives on Pennsylvania Avenue to the Capitol for the Inauguration of President-elect Donald Trump on Jan. 20, 2017, in Washington.PTI