'Women on 20s' to Ask President Obama to Put One of These 4 Women on $20 Bill

— -- A woman could soon be the new face of the U.S. $20 bill.

The nonprofit campaign "Women on 20s" allowed voters to choose three of 15 women candidates for the $20 bill, and now it's down to the "Final Four," and you can vote for the ultimate winner. The candidates are Eleanor Roosevelt, Harriet Tubman, Rosa Parks and Wilma Mankiller.

"In the past 48 hours since the final round started, we’ve had 60,000 people cast votes already," the group's executive director, Susan Ades Stone. told ABC News today. "Though all these women and many more deserve to be honored, the winner will be a symbol of what we hope are greater things to come."

Here are key facts and fun trivia on the final four women, according to their bios on "Women on 20s," to help inform your vote.

1. Eleanor Roosevelt, First Lady

- Roosevelt was the first U.S. president’s wife to take "an activist role and present her causes directly to the people through her own press conferences, syndicated columns and radio broadcasts."

- She was "deeply influenced by the feminist headmistress" at the boarding school she attended in London at 15.

-During World War I, Roosevelt spoke at patriotic rallies and worked with the Red Cross, "visiting wounded soldiers and working to improve conditions for the mentally ill."

- Although she initially opposed women's suffrage, she turned around and actively worked with the League of Women Voters after 1920.

- After the death of her husband, Roosevelt served as a delegate to the United Nations and "fought for the passage of the Universal Declaration of Human Rights."

2. Harriet Tubman, Abolitionist

- Tubman "returned to the South an estimated 19 times" to lead slaves to freedom to the North via the Underground Railroad.

- During the Civil War, Union soldiers relied on Tubman, who served as a spy and scout, to "guide them when poorly drawn and outdated maps could not."

- The Quaker Thomas Garrett said of her, "If she had been a white woman, she would have been heralded as the greatest woman of her age."

- After the war, Tubman "advocated for education and property for freed slaves in the South and she cared for the elderly and poor."

- After her death in 1913, she was nicknamed "General Tubman" "and laid to rest with military honors –- one of the first recorded African-American women to serve in the military."

3. Rosa Parks, Civil Rights Activist

- Parks became known as "the mother of the freedom movement" after refusing to move to the back of the bus for a white passenger in Montgomery, Alabama, in 1955.

- At the time of her arrest afterwards, she was the secretary for the Montgomery chapter of the NAACP and had "recently attended leadership training in workers' rights and racial equality."

- After her arrest, Parks worked for many years in Rep. John Conyers' congressional office and also served on the board of Planned Parenthood of America.

- Parks "grew up living with her maternal grandparents, who were former slaves, and witnessed Ku Klux Klan activity."

- President Obama has said of her, "In a single moment, with the simplest of gestures, she helped change America and changed the world. ... She takes her rightful place among those who shaped this nation’s course."

4. Wilma Mankiller, Cherokee Nation Leader

- Mankiller was the "first elected female chief of a Native nation in modern times."

- She "advocated for extensive community development, self-help, education and healthcare programs that revitalized the Nation of 300,000 citizens."

- Mankiller's "family name refers to a traditional Cherokee rank."

- She was awarded the Presidential Medal of Freedom in 1998, the highest honor given to civilians in the United States.

- Mankiller has also taught at Dartmouth College as a guest professor.

After the voting period ends (an end date has yet to be decided), the "Women on 20s" campaign will ask President Obama to start the process of getting the winning woman on the bill, Stone said.

The group is hoping to have the bill approved by the year 2020, which marks the centennial of the passage of the 19th Amendment that granted women the right to vote.