Donald Trump and Hillary Clinton may someday be competitors, but the Republican and Democratic presidential candidates have enjoyed financial and personal ties over the years.

Bill and Hillary attended Trump's wedding to Melania Knauss in 2005. A photo shows the two couples arm in arm, laughing and gesturing. Trump and Hillary Clinton look especially cordial. She reportedly attended the wedding ceremony, whereas Bill only attended the reception.

Trump and Clinton's daughters, Ivanka and Chelsea, are also reportedly friends, despite their parents feuding on the campaign trail. Ivanka, the vice president of her father's Business Empire, and Chelsea, the Clinton Foundation leader, are often seen together in New York City.

But the relationship isn't just personal.Trump has given between $100,0001 and $250,000 to the Clinton Foundation, according to the nonprofit's records. On four separate occasions, Trump has donated to Hillary Clinton, in 2002, 2005, 2006 and in 2007.

Trump also gave to Clinton's Senate campaign indirectly, due to a $125,000 donation from Trump to the Democratic Campaign Committee of New York. When asked about his donations to the Clinton Foundation, Trump has replied that he is in indiscriminate in his money lending.

"I give donations to hundreds of different groups and hundreds of different foundations," Trump said after a campaign stop in Manchester, New Hampshire. "I give it everywhere. It's supposed to be spent wisely. In some cases, foundations do not spend it fairly or wisely."

Due to these, many have wondered if Trump is a stalking horse for the Clintons. On the campaign trail, Hillary Clinton denounced Trump's offensive comments about Mexican immigrants and Sen. John McCain, R-Ariz. She calls Trump the Republican front-runner.

Trump frequently calls Clinton the worst secretary of state in U.S. history, a "sad" and "desperate" candidate. But Trump has in the past called Clinton "a terrific woman" and said that she and Rudy Giuliani "are both terrific people."