Conversation so far:
Who are The Avengers?
The Avengers are a fictional team of superheroes appearing in limited series comic books published by Marvel Comics. ... Labeled Earth's Mightiest Heroes, the Avengers originally consisted of Ant-Man, the Hulk, Iron Man, Thor, and the Wasp.

Question: Tell me about their first appearance
Self-contained rewrite: Tell me about The Avengers' first appearance.