Industrial Light and Magic had a bunch of ideas, but ended up building giant models for stop-motion animation.
Filmmakers may be able to do more now with a computer-generated effects, but I think special effects were more interesting in the days before digital. If you agree, then you should check out this old featurette on the making of The Empire Strikes Back, posted the official Star Wars YouTube channel, detailing the process of making the AT-ATs walk during the battle on Hoth.
Dennis Muren, an artist from the Industrial Light and Magic effects team, explains that the team toyed with the crazy idea of creating five-foot tall moving AT-AT models, but ultimately decided to animate smaller models using stop-motion. Though they weren’t as tall as a human being, Muren says the team made the models as large as possible without making them impossible to move by hand.
Some elements, like the models, are spectacular and creative. Others, on the other hand, are pretty mundane: The snow? Yeah, that’s baking soda. That’s “movie magic” for you, though: Sometimes the simplest solutions are the best.
Source: Star Wars