What is the Hero animation in Flutter?

The Hero animation creates a smooth "shared element" transition where a widget appears to fly from one screen to another during navigation. Both the source and destination widgets must be wrapped in a Hero widget with the same tag value. Flutter automatically handles the animation between the two positions and sizes. It is commonly used for image galleries or product cards where the item image expands into a detail view. The tag must be unique among all visible Hero widgets at any given time.