The Battle of Earth was the ultimate battle for the fate of the planet and the entire universe, fought among the Avengers and their allies united against alternate timeline versions of Thanos, the Black Order, and their full arsenal of Chitauri, Sakaaran, and Outrider armies. To date, it is the largest extraterrestrial battle in Earth's history.
The battle took place in and around the demolished ruins of the New Avengers Facility in New York, shortly after it was destroyed by Thanos' flagship, the Sanctuary II. After the Avengers, united under the banner of Captain America, rallied their own defenses in the united Wakandan forces, the Masters of the Mystic Arts, the Ravagers, the Asgardians, and the Guardians of the Galaxy, both sides then collided to a head in a massive assault, fighting for possession of the Infinity Stones. Many casualties from both battlefronts resulted from the battle.
With both sides vying for supremacy, the tide turned in favor of the Avengers when Captain Marvel arrived and used her cosmic powers to destroy the Sanctuary II, which had pinned down the Avengers until that point and gave Thanos the tactical advantage. The battle came to a decisive close when Iron Man sacrificed his life to activate the completed Nano Gauntlet, wiping out Thanos and his armies, effectively avenging the resurrected trillions who previously perished in the Snap, and ending Thanos' war on Earth.
