The Treaty of Peace and Friendship between Chile and Bolivia, signed on 20 October 1904, and promulgated on 21 March 1905, established in perpetuity border between Chile and Bolivia.
The territory of Antofagasta was definitely within Chile's borders but in return Chile agreed to build a railroad that would link the cities of Arica and La Paz, Bolivia was granted free movement of commerce through Chilean territory.

In 1905, the city of Antofagasta began construction of sewers, because of existing outbreaks of bubonic plague and smallpox.
The same year was ordered, so unsatisfactory, the closure of public places, in order to prevent the spread of disease.

On 1 February 1906, the railway workers union of the "Ferrocarril de Antofagasta a Bolivia" called for a readjustment of working hours, which was rejected.
For this reason, on 6 February, from more than 3,000 workers went on strike, marching in protest to the Plaza Colon (main square).
The army opened fire on protesters, killing 58 people.
The event is known as the "Massacre of Plaza Colon".

In 1912, the British community (La Colonia Britanica) erected a clock tower, replicating Big Ben, in Plaza Colón to celebrate the republic's centenary.

In 1937, the Municipality of Antofagasta made a national call for the composition of Antofagasta's anthem.
Antonio Rendic, famous physician and poet of the city, and Juan Bautista Quagliotto, musician, claimed the right to compose the lyrics and music, respectively.
On 2 February 1948, the Mayor Juan de Dios Carmona proposed in an open session in the hall of the Municipality, the establishment of 14 February as the day of the celebration of Antofagasta, despite not being the real founding date.
Later, after the popular approval, the council approved the date.

In 1956 the Universidad del Norte (now the Catholic University of the North) was founded, due to support from the Catholic University of Valparaíso.
On 9 October, of the same year began the negotiations for the creation of the "Centro Universitario Zona Norte" (University Center North Zone), part of the University of Chile.
In 1968 the Antofagasta center of the University of Chile was inaugurated, after a university reform agreement which meant the autonomy of the University Center North Zone.
Finally in 1981, merging the offices of the University of Chile and Technical State University, giving rise to the University of Antofagasta.

On 18 June 1991, a mudslide devastated much of the city, undermining land, damaged 2,464 houses and destroyed 493 buildings.
Material damage was estimated at approximately $70,000,000.
The disaster left 92 dead, 16 missing and about 20,000 homeless.
On 30 July 1995, the city was hit by an earthquake measuring 7.3 on the Richter Scale, with an intensity VII to VIII on the Mercalli Scale.
Although the fatal balance accounted three people dead and hundred injured, structural damage was minor for the magnitude of the event.
The Treaty of Peace and Friendship between Chile and Bolivia, signed on 20 October 1904, and promulgated on 21 March 1905, established in perpetuity border between Chile and Bolivia. The territory of Antofagasta was definitely within Chile's borders but in return Chile agreed to build a railroad that would link the cities of Arica and La Paz, Bolivia was granted free movement of commerce through Chilean territory.
In 1905, the city of Antofagasta began construction of sewers, because of existing outbreaks of bubonic plague and smallpox. The same year was ordered, so unsatisfactory, the closure of public places, in order to prevent the spread of disease.
On 1 February 1906, the railway workers union of the "Ferrocarril de Antofagasta a Bolivia" called for a readjustment of working hours, which was rejected. For this reason, on 6 February, from more than 3,000 workers went on strike, marching in protest to the Plaza Colon (main square). The army opened fire on protesters, killing 58 people. The event is known as the "Massacre of Plaza Colon".
In 1912, the British community (La Colonia Britanica) erected a clock tower, replicating Big Ben, in Plaza Colón to celebrate the republic's centenary.
In 1937, the Municipality of Antofagasta made a national call for the composition of Antofagasta's anthem. Antonio Rendic, famous physician and poet of the city, and Juan Bautista Quagliotto, musician, claimed the right to compose the lyrics and music, respectively. On 2 February 1948, the Mayor Juan de Dios Carmona proposed in an open session in the hall of the Municipality, the establishment of 14 February as the day of the celebration of Antofagasta, despite not being the real founding date. Later, after the popular approval, the council approved the date.
In 1956 the Universidad del Norte (now the Catholic University of the North) was founded, due to support from the Catholic University of Valparaíso. On 9 October, of the same year began the negotiations for the creation of the "Centro Universitario Zona Norte" (University Center North Zone), part of the University of Chile. In 1968 the Antofagasta center of the University of Chile was inaugurated, after a university reform agreement which meant the autonomy of the University Center North Zone. Finally in 1981, merging the offices of the University of Chile and Technical State University, giving rise to the University of Antofagasta.
On 18 June 1991, a mudslide devastated much of the city, undermining land, damaged 2,464 houses and destroyed 493 buildings. Material damage was estimated at approximately $70,000,000. The disaster left 92 dead, 16 missing and about 20,000 homeless. On 30 July 1995, the city was hit by an earthquake measuring 7.3 on the Richter Scale, with an intensity VII to VIII on the Mercalli Scale. Although the fatal balance accounted three people dead and hundred injured, structural damage was minor for the magnitude of the event.
Antofagasta