Katy Perry performed hit song 'Firework' in the inauguration concert of US President Joe Biden and Vice President Kamala Harris. (Video: Biden Inauguration Committee)

Official Video by Laura Benanti, performing (Everybody's Waitin' For) The Man with a Plan. A Christmas tribute to President Elect Joe Biden and Vice-President Elect Kamala Harris.

President-elect Joe Biden and Vice President-elect Kamala Harris participate in a ceremonial lighting around the Lincoln Memorial Reflecting Pool in honor of those lost to COVID-19. The incoming administration encouraged Americans to light a candle in their windows to join the commemoration.

Pop superstar Lady Gaga performs a rendition of “The Star Spangled Banner” at the inauguration of President-elect Joe Biden and Vice President-elect Kamala Harris.

Great performance by Demi Lovato during the Biden/Harris Presidential and Vice Presidential Inauguration. OMG!!! This makes me beyond HAPPY!!!!! Welcome back, America!!!!

Singer Jennifer Lopez performs at the inauguration of Joe Biden and Kamala Harris.

Three presidents of the United States of America: one message of unity.Watch Presidents Barack Obama, George Bush, and Bill Clinton's special message to President Joe Biden.

Amanda Gorman, a 22-year-old poet, read an original work at President Joe Biden’s inauguration on Jan. 20. After Biden was sworn in as the nation’s 46th president, Gorman read “The Hill We Climb,” building on a tradition of poets -- including Robert Frost, Maya Angelou, Elizabeth Alexander and Rich