The Meteor Attack on Buenos Aires occurred in the 23rd century as a meteor struck the city of Buenos Aires, capital of Argentina, provoking total destruction of the city, killing over 8.7 Million, and wounding a further 12.5 million.
Thirty years before the First Interstellar War, a bug spore pod from the Klendathu System landed on Mars however due to the lack of an atmosphere on Mars all bugs present inside the pod were killed. After an investigation of Klendathu, humanity discovered the Arachnid race. However, the investigation team was almost wiped out. The event lead to the establishment of the Arachnid Quarantine Zone.
Thirty years later, the Rodger Young would encounter a asteroid which was only detected when its gravity well started to effect the ship. This meteor would knock out the Rodger Young's communication systems. Unable to warn the Federation the asteroid proceeded to Earth undetected and destroyed the city of Buenos Aires.
The United Citizen Federation quickly analyzed the data from the meteor impact and determined it originated from the Arachnid's home world. The Federation then claimed that the Arachnid launched a "Bug Meteor" using Bug Plasma from the Klendathu system towards Earth and destroyed the city of Buenos Aires.
After the incident, the Federal Council voted unanimously to declare war on the Bugs and began preparations for the invasion of Klendathu. This incident also lead to an expansion of planetary defenses to ensure future meteors could be detected and destroyed before they reached Earth. At least 1 other Bug Meteor was shown to have "targeted" Earth, however, it was destroyed via defenses installment on Luna Base.