The towering political figures who died in 2018

John McCain, Republican senator from Arizona, died on August 25, 2018 at the age of 81 due to complications stemming from an aggressive form of brain cancer.

An internationally-known Vietnam War hero, McCain was imprisoned and brutally tortured for six years by North Vietnamese forces who shot down his plane in 1967. After his release, McCain received two Purple Hearts and became a politician, winning an Arizona congressional seat in 1982.

He went on to run for Senate, ultimately being reelected five times, most recently in 2016. Known as a “maverick” for his ability to compromise between parties, McCain was the 2008 Republican nominee for president. After losing to Barack Obama, he returned to the Senate and continued serving even after being diagnosed with brain cancer in 2016.

A staunch critic of Donald Trump, McCain cast a remarkable vote against the repeal of Obamacare, his last signature political moment.

The former first lady and wife of George H.W. Bush died in her Houston home on April 17, 2018, at the age of 92.

Barbara Bush first met the future president at the age of 16, marrying him four years later. Together they had six children, including former president George W. Bush. As George's political career blossomed, Barbara remained by his side, moving with him around the country and the world.

As first lady, Barbara was known for her charitable work leading the Barbara Bush Foundation for Family Literacy. After leaving the White House in 1993, she continued her philanthropic work and split her time between Texas and Maine.

She supported the presidential campaigns of her sons George and Jeb in 2000 and 2016, respectively, and was widely respected for her dedication to her family.

Her marriage to Bush Sr. was the longest in US presidential history and was famed for its ongoing dedication -- after 73 years of marriage, they still said "I love you" every night.

Winnie Madikizela-Mandela, South African anti-apartheid activist and second wife of Nelson Mandela, died on April 2, 2018 at the age of 81 after a long illness that had her in and out of the hospital.

Known as the "Mother of the Nation" due of her fight against the rule of South Africa's white minority, Madikizela-Mandela played a major role in the struggle to end apartheid as her husband spent 27 years in prison.

She remained politically active even after her divorce from Mandela in 1996, serving as a member of South Africa's parliament until the time of her death.

A long-time member of the country's ruling African National Congress, Madikizela-Mandela remained a controversial but loved figure in South African history.

"America's Pastor" Billy Graham died on February 21, 2018, at the age of 99 in North Carolina.

For six decades, Graham redefined American evangelical Christianity — beginning his career practicing sermons in Florida swamps, preaching to birds and trees. He went on to advise presidents and reach millions through televised sermons.

Graham is credited with saving broadcast evangelism and his live sermons in cities like New York and Los Angeles drew hundreds of thousands of believers.

Reynaldo Bignone, the last leader of Argentina's "Dirty War," died at the age of 90 on March 7, 2018, while serving a life sentence after being convicted of several crimes against humanity.

Bignone, who rose to power in 1982 as the successor of Leopoldo Galtieri, pledged to restore democracy to Argentina. Before doing so, however, he launched a process to destroy evidence of the country's bloody and repressive dictatorship.

Multiple Argentinian court rulings found Bignone guilty of torture and killings. He was sentenced in 2016 for his role in Operación Cóndor, an effort by Argentina's right-wing dictatorship to kidnap and assassinate dissidents that left between 60,000 and 80,000 leftist sympathizers dead across South America.

Linda Brown, who as a third grader became the center of Brown v. Board of Education, the Supreme Court case that ended segregation in American schools, died at age 75 on March 25, 2018.

Brown was nine years old when her father tried to enroll her in the Sumner School, an all-white institution in Topeka. When she was rejected, her father sued the city's board of education, becoming the leading plaintiffs in a case taken to the Supreme Court in 1952. In 1954, the court ruled that "separate education facilities are inherently unequal" and a violation of the 14th Amendment.

Despite the fight, Brown never attended Sumner, since she was in junior high by the time the ruling passed. In 1979, she became a plaintiff in the revived case after finding that the school district had not maintained its commitment to de-segregate.

Anna Mae Hays, who became the country's first female general after serving in the army during three wars, died on January 7, 2018, at the age of 97.

Hays, the daughter of Salvation Army officers, was a front-line nurse who paved the path for other women in the military by changing the way the Army viewed motherhood, service and deployment. She helped modernize the use of nurses in Army service and oversaw a jump in the number of nurses deployed.

Hays retired from the military in 1971, after three decades of service.

Kofi Annan, who was the first black African secretary general of the United Nations, died on August 18, 2018, at the age of 80 in Switzerland.

A Ghanaian diplomat, Annan received the Nobel Peace Price in 2001 for his work revitalizing the U.N. During his two terms as the organization's leader, from 1997 to 2006, Annan oversaw the strengthening of the U.N.'s peacekeepers and the creation of the organization's Peace building Commission and Human Rights Council.

Democratic U.S. Representative Louise Slaughter, a Kentucky blacksmith's daughter who became a leading progressive voice in Congress from New York, died at age 88 in Washington, D.C.

Born in Kentucky, Slaughter was first elected to Congress in 1986. She served as chair of the powerful House Rules Committee from 2007 to 2011, the first woman to hold the position. At the time of her death, Slaughter was the top Democrat on the panel.

One of the longest-serving women in the House of Representatives, Slaughter fought for the rights for women and minorities throughout her tenure. She backed the Affordable Care Act, the Lily Ledbetter Fair Pay Act and student aid legislation.