Are apes the better human beings? Or, put differently, are there good and evil members of every species? These are some of the timeless themes that "Planet of the Apes" grappled with when it hit theaters on February 8, 1968. It looked at questions of morality and ethics, humanity and the justifiable boundaries of science and research, as did many of the subsequent sequels, remakes and spinoffs.

The movie was based on the book "La Planète des singes" by French author Pierre Boulle, who wrote the work in 1963 after reportedly observing the human-like behavior of gorillas at the zoo. It was first translated into English in 1964 under the title "Monkey Planet." Only later did it receive the renowned title that it shares with the iconic movie: "Planet of the Apes."

Director Franklin J. Schaffner created the film version of the book that starred Charlton Heston (left) as Taylor, the main astronaut stranded on an ape-inhabited planet, and Kim Hunter (right), a psychologist from the simian planet. It was an immediate hit with both critics and audiences. Make-up artist John Chambers also received an Oscar for his groundbreaking prosthetic work.

The final post-apocalyptic scene in the 1968 film was one of the legendary movie moments of the decade: Taylor rides horseback with a little girl on a beach and comes across the remains of the Statue of Liberty. The realization that they'd been on an Earth devastated by nuclear war the whole time — and not on a far-away planet — was a shocking revelation for audiences living during the Cold War.

The success of the 1968 film led to four sequels: "Beneath the Planet of the Apes" (1970); Escape from the "Planet of the Apes" (1971); "Conquest of the Planet of the Apes" (1972); and "Battle for the Planet of the Apes" (1973). Two TV series were also broadcast in the 1970s. Decades later, Tim Burton directed a remake of the original in 2001 (above) starring Mark Wahlberg.

After the remake, an entirely new concept was developed for the franchise: the story about the main chimpanzee in the original was reinvented by drawing on the contemporary advances in genetic engineering. The result was three new films. Part of the success behind the "Planet of the Apes" franchise has been its ability to combine present-day topics with exciting action and compelling characters.

The most recent movie in the rebooted series, "War for the Planet of the Apes" (above), was released in 2017. It is a prehistory of the original film tale that continued the focus on the chimpanzee Ceaser, a thoughtful and nuanced character. Like the 1968 original, the latest film also showcases war between humans and apes. Speculation abounds as to whether another reboot film is yet to come.

While another "Planet of the Apes" film may or may not hit the big screens in the future, the original has given audiences over five decades food for thought. It questions the meaning of life and considers the relationship between humans and animals. That human beings do not necessarily get higher marks than apes is only one surprising insight that viewers still gain when viewing the film today.

The first "Planet of the Apes" film was released in 1968 and turned out to be a huge hit. Now, nearly 50 years later, a ninth film in the ape saga is hitting theaters, but it is not a continuation of the story. Instead, it's the prehistory of the original film tale.

"War for the Planet of the Apes," which opens in US theaters on July 14, again showcases the basic conflict between humans and apes, which are, in part, genetically manipulated. Woody Harrelson plays the crazed US Colonel who faces off with the apes.

The strength of the "Planet of the Apes" films has been that the producers, authors, and directors of the saga have always valued nuanced, well-rounded film characters. The latest film attests to that: Ape is not just ape. Various species are defined by various features - and a little girl acts as a bridge between humans and apes.

The small, mute girl, played by Amiah Miller, is seized by the apes during the tumult of war. They first want to do away with her, but then show they have a heart after all. They see the little girl for what she is - a person who has not succumbed to human perfidy - and end up taking her in.

"War for the Planet of the Apes," whose plot largely plays in the wild, snowy landscapes of North America, radiates with many impressive panoramas of nature. It was filmed in part using a 65-mm camera - a format which makes particularly large, sharp images possible. It was also partially filmed in 3D.

Despite the metaphysical context of the film plot, fans of action films will also get their fill. The final sequence in particular, in which the Colonel's troops (including slave apes) face off with the freed members of the same species, is action-packed.

In 1968, director Franklin J. Schaffner created a modern film legend with "Planet of the Apes." Charlton Heston played the leading role of a human who gets closer to the apes (pictured). With production costs totalling nearly $6 million, the film earned many times that at the box office.

Following the huge success of the original 1968 film, four others followed by 1973. Then there was a single remake in 2001. A decade later, a trilogy kicked off, with the last one "War for the Planet of the Apes" now hitting theaters around the world.

The second to last film of the popular series was released in theaters in 2014: "Dawn of the Planet of the Apes," directed by Matt Reeves. Reeves also directed the latest "War" film, which links back to its predecessor.

"War for the Planet of the Apes" opens in Great Britain and Ireland on July 11, and in theaters in other countries later in the week. German fans have to wait until August 3 to see the film.