This is Spielberg’s ‘master image’, according to the man himself. He says it encapsulates everything about his film-making - the blend of danger and wonder and the openness of the child to it.
"That beautiful but awful light, just like fire coming through the doorway. And he’s very small, and it’s a very large door, and there’s a lot of promise or danger outside that door."
To be honest, I disagree with Spielberg on this. I think this is one of a handful of images that are absolutely key to his film-making (the Moon shot in ET: The Extra-Terrestrial is an obvious one, along with the shot of Francois Truffaut signing to the aliens at the end of CE3K), but you can see why he holds this in such high regard.
Not only is there a real sense of magic to the scene, but like so many of Spielberg’s truly great moments, it’s purely cinematic. No dialogue, just sight and sound combining in a majestic spectacle. A brilliant and hugely affecting piece of cinema.