Spain's Basque region reached a quiet but major milestone earlier this month in the fight against homegrown terrorism. The Basque militant group ETA formally surrendered its weapons to French authorities, ending one of the longest armed conflicts in modern history.

Santurtzi, Northern Spain | (Inset) March 4, 2006: Basque riot police clashed with pro-independence followers during a funeral for an ETA member. | (Photo) April 4, 2017 | (AP Photo/Alvaro Barrientos)

Nautical Promenade, Gexto | (Left) May 19, 2008: The wreckage from an ETA car bomb. | (Right) April 4, 2017. | (AP Photo/Alvaro Barrientos)

ETA — which stands for Euskadi ta Askatasuna, meaning Basque Country and Freedom — first emerged in the 1950s in response to the brutal cultural repression of the Basque peoples under Spanish dictator General Francisco Franco. The armed faction began an aggressive campaign for an independent homeland that spiraled into violent clashes between national authorities and the Basque separatists. Since those first years more than half a century ago, ETA has killed more than 850 people.

Associated Press photographer Alvaro Barrientos has been covering this relentless regional war along the Spanish-French border for the past two decades. During that time, the ETA's deadly turmoil had already woven itself into the fabric of daily life.

"The anxiety always started at 8 on the dot," Barrientos writes in a reflective op-ed. "Day after day, for 20 years, the morning radio news bulletin woke us with the latest atrocity. One day, a shootout, another, a kidnapping and, next, maybe a massive car bomb explosion. Later, the death toll and names of victims would emerge, followed by the usual round of political explanations."

San Sebastian | (Top) Sep. 14, 2008: Pro-independence demonstrators throw stones and bottles at Basque police, who tried to disperse the illegal street protest held by several thousand ETA supporters. | (Bottom) April 3, 2017. | (AP Photo /Alvaro Barrientos)

After years of piercing terror, the war ended with a whisper: The ETA declared a truce in 2011, and though attacks and riots continued in the years following, their scale and furor fizzled. Some speculate the rise of the Islamic State contributed to the Basque organization's decline — as local and international disdain for ISIS spread, it became increasingly unpopular to join the ranks of such a destructive group.

The small Basque town of Legutiano | (Top) May 14, 2008: A police station destroyed by an ETA car bomb that killed one officer and injured four. | (Bottom) April 4, 2017. | (AP Photo/Alvaro Barrientos)

Following the group's disarmament, Barrientos revisited places where the internal mayhem had come to an ugly head. Juxtaposed, his images from then and now trace the striking perseverance of a community under attack.

"Looking back, you find yourself asking how society put up with the violence for so long," Barrientos says. "Our society has matured. Now one can breathe easily on the street, although the uneasiness has not disappeared altogether."

San Sebastian | (Top) Oct. 26, 2003: Masked ETA followers prepare to fight against the police during an illegal rally. | (Bottom) April 3, 2017. | (AP Photo /Alvaro Barrientos)

Shopping center, Urdax | (Top) Feb. 15, 2006: The remnants of a car bomb and its wreckage. | (Bottom) April 4, 2017. | (AP Photo/Alvaro Barrientos)

San Sebastian | (Top) Sept. 14, 2008: Riot police detain an unidentified pro-independence Basque demonstrator during an illegal street protest by several thousand ETA supporters. | (Bottom) April 3, 2017. | (AP Photo/Alvaro Barrientos)

San Jose Church, Bilbao | (Top) June 20, 2009: Funeral procession for Spanish National Police officer Eduardo Garcia Pueyes, who was killed after a bomb planted in his car by the ETA exploded. | (Bottom) April 3, 2017. | (AP Photo/Alvaro Barrientos)