Delegates from New York hold signs in support of Hillary Clinton, 2016 Democratic presidential nominee, during the Democratic National Convention (DNC) in Philadelphia, Pennsylvania, U.S., on Tuesday, July 26, 2016. Democrats began their presidential nominating convention Monday with a struggle to fully unite the party, following a dramatic day of internal squabbling and protests.

Photographer: Andrew Harrer/Bloomberg

Delegates from New York hold signs in support of Hillary Clinton, 2016 Democratic presidential nominee, during the Democratic National Convention (DNC) in Philadelphia, Pennsylvania, U.S., on Tuesday, July 26, 2016. Democrats began their presidential nominating convention Monday with a struggle to fully unite the party, following a dramatic day of internal squabbling and protests.

Photographer: Andrew Harrer/Bloomberg

The 2016 Democratic National Convention in Pictures

This week, the Democrats descend on Philadelphia, the historic City of Brotherly Love, for their convention. The party is seeking to hold on to the presidency in a country that's becoming younger, more ethnically diverse, less religious, and more liberal on a variety of issues.

Hillary Clinton, the 2016 Democratic presidential nominee, on stage during the convention, on Thursday night, July 28, 2016.

Photographer: Daniel Acker/Bloomberg

Hillary Clinton, left, holds hands with her daughter, Chelsea Clinton, on stage during the convention on Thursday, July 28, 2016.

Photographer: Daniel Acker/Bloomberg

Katy Perry performs during the convention on Thursday, July 28, 2016.

Photographer: Andrew Harrer/Bloomberg

A delegate adjusts his tie during the convention on Thursday, July 28, 2016.

Photographer: Victor J. Blue/Bloomberg

Khizr Khan, father of fallen soldier Humayun S. M. Khan, pauses while speaking during the convention on Thursday, July 28, 2016.

Photographer: John Taggart/Bloomberg

U.S. President Barack Obama and Hillary Clinton, 2016 Democratic presidential nominee, wave on stage during the Democratic National Convention in Philadelphia on Wednesday night, July 27, 2016. 

Photographer: Daniel Acker/Bloomberg

Obama speaks during the convention on Wednesday, July 27, 2016.

Photographer: Andrew Harrer/Bloomberg

Delegates cheer during Obama's speech at the convention on Wednesday, July 27, 2016.

Photographer: Andrew Harrer/Bloomberg

U.S. Vice President Joseph "Joe" Biden gestures while arriving on stage during the convention on Wednesday, July 27, 2016. 

Photographer: Andrew Harrer/Bloomberg

A delegate wears a sticker reading "Thump Trump" during the convention on July 27, 2016. 

Photographer: Andrew Harrer/Bloomberg

Michael Bloomberg, founder of Bloomberg LP, speaks during the convention, on Wednesday, July 27, 2016. 

Photographer: Andrew Harrer/Bloomberg

Gabrielle "Gabby" Giffords, former U.S. Representative from Arizona, left, holds hands with Former NASA Astronaut Mark Kelly during the convention on Wednesday, July 27, 2016.

Photographer: Daniel Acker/Bloomberg

Lenny Kravitz performs at the convention on Wednesday, July 27, 2016.

Photographer: Andrew Harrer/Bloomberg

Tim Kaine, 2016 Democratic vice presidential nominee, gestures with his wife Anne Holton on stage during the convention on Wednesday, July 27, 2016.

Photographer: Andrew Harrer/Bloomberg

Sebastien De La Cruz performs the national anthem at the start of day three of the convention on Wednesday, July 27, 2016.

Photographer: David Paul Morris/Bloomberg

Julian Castro, secretary of U.S. Housing and Urban Development, and Representative Joaquin Castro, a Democrat from Texas, gesture on stage during a walk through before the start of the convention, on Wednesday, July 27, 2016.

Photographer: John Taggart/Bloomberg

Photographers stand as Hillary Clinton speaks on screen during the convention on Tuesday, July 26, 2016.

Photographer: David Paul Morris/Bloomberg

Former president Bill Clinton arrives on stage during the convention on Tuesday, July 26, 2016.

Photographer: John Taggart/Bloomberg

Senator Bernie Sanders, an independent from Vermont, center, pauses while standing with delegates from Vermont during a roll call vote at the convention, where he moved to give Hillary Clinton the party's presidential nomination by acclamation on Tuesday, July 26, 2016.

Photographer: John Taggart/Bloomberg

Stephanie Rawlings-Blake, mayor of Baltimore, right, receives the Kansas tally during a roll call vote at the convention on Tuesday, July 26, 2016.

Photographer: Andrew Harrer/Bloomberg

Members of Mothers of the Movement stand on stage during the convention on Tuesday, July 26, 2016.

Photographer: David Paul Morris/Bloomberg

A delegate wears a "Black Lives Matter" sticker over her mouth during the convention on Tuesday, July 26, 2016.

Photographer: John Taggart/Bloomberg

Actress Elizabeth Banks during a speech at the convention on Tuesday, July 26, 2016.

Photographer: David Paul Morris/Bloomberg

Actors Lena Dunham, left, and America Fererra arrive on stage during the convention on Tuesday night, July 26, 2016.

Photographer: Victor J. Blue/Bloomberg

Supporters of Bernie Sanders touch hands through the glass of the media tent while demonstrating outside the convention on Tuesday, July 26, 2016.

Photographer: Andrew Harrer/Bloomberg

First Lady Michelle Obama smiles while speaking during the convention on Monday night, July 25, 2016. 

Photographer: Andrew Harrer/Bloomberg

Comedian Sarah Silverman, right, reacts on stage with Senator Al Franken, a Democrat from Minnesota, during a speech at the convention on Monday, July 25, 2016.

Photographer: Daniel Acker/Bloomberg

Actress Eva Longoria, left, greets Senator Cory Booker, a Democrat from New Jersey, on stage during the convention on Monday, July 25, 2016. 

Photographer: Andrew Harrer/Bloomberg

Al Franken walks off stage during the convention on Monday, July 25, 2016. 

Photographer: David Paul Morris/Bloomberg

Representative Joe Kennedy, a Democrat from Massachusetts, speaks to members of the media during the convention on Monday, July 25, 2016. 

Photographer: John Taggart/Bloomberg

Senator Bernie Sanders, an independent from Vermont, speaks during the convention on Monday night, July 25, 2016. 

Photographer: John Taggart/Bloomberg

Delegates hold signs after the start of the convention on Monday, July 25, 2016.

Photographer: Daniel Acker/Bloomberg

Stephanie Rawlings-Blake, mayor of Baltimore, swings the gavel during the beginning of the Democratic National Convention in Philadelphia on Monday, July 25, 2016.

Photographer: Daniel Acker/Bloomberg

A delegate wears a "Feel The Bern" jacket during the convention in Philadelphia on Monday, July 25, 2016.

Photographer: Andrew Harrer/Bloomberg

A delegate wears a hat topped with a Hillary Clinton bobble head.

Photographer: Andrew Harrer/Bloomberg

Delegates hold signs protesting the Trans-Pacific Partnership during the convention on Monday, July 25, 2016.

Photographer: Andrew Harrer/Bloomberg

A delegate wears a hat with a pin supporting Hillary Clinton before the convention begins in Philadelphia on Monday, July 25, 2016. 

Photographer: Daniel Acker/Bloomberg

Senator Bernie Sanders, an independent from Vermont, waves while arriving on stage on Monday during a walk-through at the Wells Fargo Center.

Photographer: David Paul Morris/Bloomberg

Singer Demi Lovato rehearses on Monday.

Photographer: John Taggart/Bloomberg

Senator Elizabeth Warren (D-Mass.) gestures on stage during a convention walk-through in Philadelphia on July 25, 2016.

Photographer: Andrew Harrer/Bloomberg

Protesters supporting Sanders demonstrate during a rally at Philadelphia City Hall on Monday, July 25, 2016.

Photographer: Victor J. Blue/Bloomberg

Stephen Colbert smiles while performing on the floor of the Wells Fargo Center on Sunday, July 24, 2016.

The Reverend Jesse Jackson tours the floor ahead of the convention on Sunday.

Photographer: Andrew Harrer/Bloomberg

A teleprompter sticking out of the stage floor.

Photographer: Daniel Acker/Bloomberg

Workers adjust the podium on Monday, before the start of the Democratic National Convention in Philadelphia.

Photographer: Daniel Acker/Bloomberg

Signs lie discarded at Philadelphia City Hall after a Clean Energy March on Sunday, a day before the start of the convention.

Photographer: Victor J. Blue/Bloomberg

Protesters demonstrate at a "March For Bernie" down Philadelphia's Broad Street on Sunday, July 24, 2016. 

Photographer: Victor J. Blue/Bloomberg

Paul Simon rehearses on stage on Sunday. 

Photographer: Andrew Harrer/Bloomberg

A protester sports a Bernie Sanders tattoo in Philadelphia on July 24, 2016. 

Photographer: Victor J. Blue/Bloomberg

A young man proudly displays his shirt at a market in Philadelphia's Center City on July 24, 2016.

Photographer: John Taggart/Bloomberg