In the movie "The Avengers" (2012), the original six Avengers are: 1. Iron Man (Tony Stark) 2. Captain America (Steve Rogers) 3. Thor 4. Hulk (Bruce Banner) 5. Black Widow (Natasha Romanoff) 6. Hawkeye (Clint Barton) These characters unite to form the Avengers team in order to combat the threat posed by Loki and his alien army. Each character brings unique skills and abilities, making them a formidable group.

In the 1960s, "The Avengers" primarily refers to the British television series featuring secret agents John Steed and his various partners, notably Emma Peel, played by Diana Rigg. The show combined elements of espionage, science fiction, and action, becoming iconic for its stylish presentation and clever dialogue. It aired from 1961 to 1969 and did not relate to Marvel's superhero team, which also shares the name "The Avengers" but was more prominently featured in comics and later films.

In "The Avengers," the "big three" refers to the core characters who are central to the team's identity: Iron Man (Tony Stark), Captain America (Steve Rogers), and Thor. Iron Man is a genius billionaire with a high-tech suit, Captain America is a super-soldier and symbol of justice, and Thor is the God of Thunder with incredible strength and control over lightning. Together, they lead the Avengers in their mission to protect Earth from formidable threats.

Diana Rigg left the British TV series "The Avengers" after its fifth season in 1968, primarily due to a desire to pursue other acting opportunities and to avoid being typecast as her iconic character, Emma Peel. Rigg sought to broaden her career, and after leaving the show, she successfully transitioned to film and theater, gaining acclaim for her performances in various roles. Her departure marked the end of a significant era for the series, which had gained a strong following during her tenure.