The second trilogy, forming a prequel to the original films, was based on "The Hobbit" and starred Martin Freeman as Frodo's cousin Bilbo Baggins. Ian Holm also briefly appeared in both trilogies as an older Bilbo, happily retired in his home in the Shire.

Frodo and Bilbo are sent out on their adventures by the wizard Gandalf, played by Sir Ian McKellen.

My precious! Among the more memorable characters in the series is Gollum, corrupted by the power of the ring and played in fine style by Andy Serkis.

Aragorn, son of Arathorn, leads the Fellowship, as Strider the Ranger of the North. Played by Viggo Mortenson, he's a bit handy with a sword.

Cate Blanchett appears in the series as the ethereal Galadriel.

The first trilogy of movies kicked off with "The Fellowship of the Ring" in 2001, developed by Peter Jackson since 1995. The films were largely shot at the same time in New Zealand and cost roughly $300 million.

The Fellowship is a band of warriors and hobbits joining Frodo and Gandalf. Its members are played by Orlando Bloom, Sean Bean, Viggo Mortenson, Billy Boyd, Sean Astin, Dominic Monaghan and John Rhys-Davies.

This wasn't the first attempt to bring JRR Tolkien's Middle-earth to the big screen: the Beatles wanted to play the Hobbits under Stanley Kubrick's direction, John Boorman had a crack at a script, and live action versions were made in the Soviet Union in the 1980s and Finland in the 1990s.

Seen here, though, is the Fellowship of the Ring as seen in a 1978 animated version adapted by "Fritz the Cat" creator Ralph Bakshi.

Older "LoTR" fans will remember being terrified by the animated Ringwraiths.

Effects have moved on since then: the combination of Andy Serkis' motion capture performance with groundbreaking computer-generated effects brought Gollum to life and paved the way for kiwi effects company Weta Workshop to create jaw-dropping effects in films like "Avatar" and "Rise of the Planet of the Apes."

Jackson and Weta also pushed the boundaries of special effects and technology involving the use of green-screen, filming in 3D and even 48 fps (frames per second) high-frame-rate filming.

Another memorable character is the gravity-defying, archery-loving elf Legolas Greenleaf, played by a well-moisturised Orlando Bloom.

Also part of the Fellowship is Boromir. Sheffield actor Sean Bean later appeared in the TV show "Game of Thrones," another fantasy epic based on a series of beloved novels, this time written by George RR Martin.

"And my axe!" The dwarf Gimli, played by John Rhys-Davies, provided much of the first trilogy's comic relief.

Every saga needs a bad guy, and here's ours: Sauron. Boo! Hiss!

It was Sauron who plotted the forging of the Rings of Power, including the One Ring to rule them all. Which makes him the Lord of the Rings mentioned in the series title.

The second film in the series, released in 2002, took us to "The Two Towers." The titular towers are Barad-dûr, home of Sauron, and Orthanc, the black tower of Isengard where the sorcerer Saruman hangs his beard.

The final film in the first trilogy -- and the end of the saga when taken chronologically -- is 2003's "The Return of the King." With extra scenes added for the Extended Editions released on DVD, the trilogy is more than 11 hours long.

The unsung hero of "Lord of the Rings" who sticks with Frodo all the way up Mount Doom: Samwise Gamgee, played by Sean Astin.

The original three movies all came down to this: can Frodo cast the Ring of Power into the Crack of Doom, foiling Sauron for good?

The second trilogy is set 60 years before the first and tells the story of how Bilbo acquired the one ring. They were originally set to be directed by Guillermo del Toro, before Jackson stepped back into the director's chair.

Bilbo is recruited by a group of dwarves led by Thorin Oakenshield in a quest to slay a dragon and reclaim their homeland of Erebor.

In the second film, "The Desolation of Smaug," a younger, harder Legolas joins the quest.

Alongside Legolas is the pointy-eared Tauriel, played by "Lost" star Evangeline Lilly.

Luke Evans is Bard the Bowman, who has a family feud with Smaug the dragon.

Richard Armitage is Thorin, the dwarf king with a dangerous thirst for gold.

The quest takes Bilbo and the dwarves across Middle-earth.

Boss orc Azog the Defiler tracks the dwarves on their journey.

The quest takes Bilbo into the gold-strewn lair of Smaug.

The fiendish Smaug is voiced by Benedict Cumberbatch.

Gandalf is joined by fellow wizard Radagast the Brown, played by none other than the seventh star of "Doctor Who," Sylvester McCoy.

The sixth and final film to be produced is "The Battle of the Five Armies," premiering in December 2014.

Once again it's up to Bilbo to save Middle-earth.

Lee Pace is the Elf King Thranduil, father of Legolas.

At the "Five Armies" premiere in London's Leicester Square, devoted fans in costume camp out to meet stars such as Sir Ian McKellen and Orlando Bloom.

The tranquil Bag End, home of Bilbo and later Frodo Baggins, is the start of many an adventure. You can now visit Hobbiton in New Zealand, home of much of the breathtaking scenery in the films.

Christopher Lee, who plays the fallen wizard Saruman, is the only cast member to have met the author of the Middle-earth novels, JRR Tolkien.

The films have spawned all manner of memes, from the "Taking the Hobbits to Isengard" song to the classic "One does not simply..."

The series have also birthed spin-offs and memorabilia, from video games to replica swords and armour. Here we see -- wait for it -- Lego Legolas.

The two trilogies have collectively been nominated for 36 Academy Awards. Here, Peter Jackson celebrates the 17 Oscars won by the first trilogy, including Best Director and Best Picture for "The Return of the King."

Cast members of "The Hobbit" and "Lord of the Rings" gather with Peter Jackson for the final time on the green carpet at the "Five Armies" premiere. We'll miss you guys.

One ring to rule them all, one ring to find them. One ring to bring them all, and in the darkness bind them.