The middle section of Peter Jackson's history-making trilogy introduced new eye-boggling elements, arguably bettering its expectation-defying predecessor.

Following the humongous success of The Fellowship of the Ring, Jackson and his collaborators no longer had to prove themselves worthy of adapting Tolkien's books and were free to simply focus on moving the story along. Which they did with gusto, unleashing some epic cinema along the way.

Sam (Sean Astin) and Frodo (Elijah Wood) are still making their way to Mordor, but they find themselves with unwanted company in the form of the ring-addicted creature Gollum (played by Andy Serkis and a whole bunch of computer guys). Aragorn (Viggo Mortensen) meanwhile is getting ready for an un-winnable battle against Sauron's forces in the stronghold of Helm's Deep and Merry and Pippin are getting to know Treebeard, the Fangorn Forrest-dwelling tree creature.

A potentially ridiculous folly, Gollum's technologically ground-breaking execution created the first ever wholly believable CGI (Computer Generated Imagery) character in the history of cinema. Combining motion capture of the actor Andy Serkis (who's performing a similar role for the title character in Jackson's forthcoming King Kong) with masterful digital animation, Gollum is a fully realised part of the Lord of the Rings universe, as tangible as Aragorn or Frodo. Plus his conflicted nature (enhanced by Serkis' voice work) serves to highlight the developing themes of the trilogy.

Other highlights of The Two Towers include the epic battle of Helms Deep - a crushing, violent conflict all the more impactful for occurring at night in the rain; the final assault on Isengard; the glimpses of the huge Oliphants and the emergence of the bigger, badder orcs, the Urukhai.

As with Fellowship, The Two Towers has fine performances across the board, and new additions Brad Dourif (as the snivelling Wormtongue); Karl Urban (as Rohan warrior Eomer); Miranda Otto (as the plucky Eowyn); Bernard Hill (as Eowyn's father King Theoden) and David Wenham (as Boromir's brother Faramir) don't let the side down.

Cited by many as their favourite of the trilogy, The Two Towers ups the emotional ante of the series while providing some eye-popping special effects coupled with rousing action scenes. Go Pete.