Short answers, pulled from the story.
Andy Serkis played the role of Gollum by providing his voice and movements on set while performing in a motion capture suit. His scenes were filmed twice with and without him to create a unique challenge for the visual effects team.
The film opened in cinemas on the 18th of December 2002. It grossed $26 million on opening day making it the second-highest opening Wednesday behind Star Wars: Episode I, The Phantom Menace.
Weta Digital produced 73 minutes of digital effects across 799 shots during the production. The staff doubled from 260 employees to accommodate this workload over Christmas 2001.
The film earned a worldwide total of $942.3 million against a budget of $94 million. It made $348.9 million in North America and $592.7 million internationally.
Alan Lee joined the project in late 1997 as the designer tasked with creating Helm's Deep at 1:35 scale. This structure was one of the first miniatures built for the film and part of the video that sold the project to New Line Cinema.