Concepcion Picciotto, known to countless people as the woman who for decades maintained a peace vigil outside the White House gates, passed on Monday at a housing facility operated by N Street Village, a nonprofit that supports homeless women in Washington, D.C.

Schroeder Stribling, the shelter’s executive director, said that Picciotto had recently suffered a fall but the immediate cause of death is still unknown. She was believed to be 80.

Often referred to as "the Little Giant," Picciotto held her protest "for world peace against the proliferation of weapons of mass destruction" in Lafayette Park since 1981. The Washington Post notes that her demonstration is "widely considered to be the longest-running act of political protest in U.S. history."

Known by Connie to her friends, Picciotto kept her vigil "through the rain and snow, the arrests, the abuses and threats through the years," according to a website dedicated to her.

A Spanish immigrant, Picciotto came to D.C. by way of New York nearly three and a half decades ago, joining the vigil's founder, William Thomas, and eventually his wife Ellen. According to the Post, "the group’s grass-roots nuclear disarmament campaign was known as Proposition One, and its crowning achievement came in 1993, when a nuclear disarmament petition circulated by the activists resulted in a ballot initiative passed by District voters."

After Thomas died in 2009, Picciotto vowed to maintain the demonstration in his honor. But her failing health in recent years forced her to scale back her protest, though young activists would help guard the vigil. When left vacant, U.S. Park Police would remove Picciotto's tent and signs.

"We have to stop the world from being destroyed," Picciotto explained in a 2013 profile. "I have to be here. This is my life."

Over the years, Picciotto spoke to millions of people about the threats of war and political corruption. After news of her death, many of her visitors—or people who simply walked by her each day—shared images and memories of her online. 

RIP #concepcionpicciotto I had the privilege of meeting you in DC. Thank you for advocating for #peace in this world.

— Maram Museitif (@MaramMPH) January 26, 2016

Rest in Peace #ConcepcionPicciotto an unyielding advocate for peace in our world. Thank you for often unrecognized loyalty to humanity

— Robert White (@RobertWhite_DC) January 26, 2016

RIP protester Concepcion Picciotto. pic.twitter.com/6S8JJHTjHy

— Ayah Alfawaris (@AyahAlfawaris) January 26, 2016

A protester against atrocities.I saw her infront of white house,Rip #ConcepcionPicciotto https://t.co/sJDwAE5mPp pic.twitter.com/BvJzfLxmnz

— Farzana MajeedBaluch (@farzana_majeed) January 26, 2016

RIP peace activist Concepción Picciotto. You may recognize her anti-nuclear arms tent outside the White House pic.twitter.com/Wr1wmc1ZgA

— shereen (@shereenashai) January 26, 2016