As Americans prepare to choose their next president, polls suggest Donald Trump and Hillary Clinton are two of the most unfavoured candidates in recent history.
Here the Press Association looks at some of the controversies that have dogged their campaigns ahead of Tuesday's vote.
:: Sexual assault allegations
A number of women have come forward to accuse Mr Trump of sexual assault.
They include Summer Zervos, a former contestant on the US version of The Apprentice, who said the property tycoon forced himself on her at a hotel and began "thrusting his genitals".
Another woman is suing Mr Trump for allegedly raping her when she was 13. She had planned to speak publicly about the lawsuit but backed out of a press conference after receiving threats, her lawyer Lisa Bloom said.
Mr Trump has insisted the sexual assault allegations are "100% made up", while his wife Melania suggested the claims had been co-ordinated by his political rivals.
:: Lewd comments about women
A 2005 video recording of Mr Trump in which he is heard talking about grabbing women ''by the p***y'' plunged his presidential campaign into turmoil.
A series of prominent Republicans withdrew their support for Mr Trump following his comments to TV presenter Billy Bush, while some called for him to drop out of the presidential race.
Mr Trump apologised for his remarks and dismissed them as "locker room talk".
Mrs Clinton said Mr Trump's comments represented "exactly who he is" after she previously criticised the Republican for calling women "pigs, slobs and dogs".
:: Failure to pay federal tax
Mr Trump admitted he used a 916 million-dollar loss he claimed in 1995 to avoid paying federal income tax.
The Republican defended his actions, saying the move was "smart" and insisted many of Mrs Clinton's donors had also taken "massive tax write-offs".
Mr Trump has refused to release his tax returns during the election campaign - unlike other candidates in recent years - saying he would not publish them before a routine audit was completed.
:: Comments on Muslims and Mexicans
Mr Trump attracted widespread criticism when he called for a ban on Muslims entering the US in the wake of the San Bernardino terrorist attack in December 2015.
He later claimed the proposal was "just a suggestion" before outlining plans for "extreme vetting" of would-be immigrants to exclude Islamic terrorists.
Mr Trump has also faced accusations of racism over his plan to build a wall separating Mexico and the United States, with the intention of keeping out illegal immigrants.
"When Mexico sends its people, they're not sending their best," he said. "They're sending people that have lots of problems. They're bringing drugs. They're bringing crime. They're rapists."
:: Use of a private email server
Mrs Clinton said she made a "mistake" over her use of a private email server for work correspondence while she was US secretary of state.
An FBI investigation concluded in July that Mrs Clinton and her staff had been "extremely careless" with classified information, but there was no evidence she knowingly shared sensitive material and criminal charges were not recommended.
Just over a week before election day, FBI director James Comey announced the case was being reopened after new emails "pertinent" to the investigation had been discovered.
The unearthed emails were found during the FBI's investigation into former US congressman Anthony Weiner, who is accused of sending sexually explicit messages to a 15-year-old and is married to Mrs Clinton's aide Huma Abedin.
Mr Trump has claimed Mrs Clinton should be in jail over the scandal and a special prosecutor will be instructed to investigate her if he is elected president.
:: Benghazi attack
Mrs Clinton says she takes responsibility for the attack on the US consulate in Benghazi, Libya, that killed four Americans in 2012.
She asked ambassador Chris Stevens - one of the four embassy staff killed - to go to Libya as US envoy while she was secretary of state.
Mr Trump claimed Mrs Clinton slept through the Benghazi attack and directly blamed her for Mr Stevens' death.
"He was left helpless to die as Hillary Clinton soundly slept in her bed," he said.
:: Clinton Foundation
Mrs Clinton has faced claims her charitable foundation had influence over the US state department during her time as secretary of state.
A batch of unreleased emails, obtained by legal group Judicial Watch, showed exchanges between the Clinton Foundation and state department employees.
Mr Trump described the Clinton Foundation as "the most corrupt enterprise in political history" - but it later emerged he had donated more than 100,000 dollars to the charity.
:: Sexual misconduct allegations against Bill Clinton
Mr Trump met women who accused the former US president of rape and other unwanted sexual advances shortly before his second US presidential debate.
The Republican claimed Mr Clinton had been "abusive to women" and Mrs Clinton should be "ashamed" for attacking her husband's accusers.
On the debate stage, Mrs Clinton did not respond directly to Mr Trump's accusations but repeated comments made by First Lady Michelle Obama - "When they go low, you go high".
Mr Clinton never faced any criminal charges in relation to the sexual misconduct allegations and a lawsuit over an alleged rape was dismissed.