By 2285, a temple had been constructed on the mountain, which incorporated an altar and an adjacent building known as the Hall of Ancient Thought. A long flight of steps led from the base of the mountain, an area that had a fountain and could be used as a landing base for craft, up to the temple. The altar was sparsely furnished and included a Vulcan gong. (Star Trek III: The Search for Spock)
In ancient Vulcan history, a story that Surak told, regarding the IDIC or "Infinite Diversity in Infinite Combination", began at Mount Seleya. As such, Mount Seleya was represented by a triangle in the IDIC symbol. In the 4th century, Surak died on the mountain from radiation poisoning, and his katra was spirited away from the area prior to the final battle between his followers and "those who marched beneath the raptor's wings." That enemy apparently left Vulcan and became the Romulans. (ENT: "The Forge")
Shortly thereafter, upon being captured while helping Jonathan Archer and T'Pau take the long-missing Kir'Shara (the record of Surak's original writings) from a sealed chamber beneath the T'Karath Sanctuary to Vulcan's capital city, T'Pol lied to her captor – Talok, a Romulan operative disguised as a Vulcan military officer loyal to the traitorous Administrator V'Las – that Archer and T'Pau were actually trying to deliver the Kir'Shara to Mount Seleya. T'Pol further claimed they were heading there because only the priests on Seleya could translate Surak's original writings from within the artifact. (ENT: "Kir'Shara")
While possessed by Spock's katra in 2285, Leonard McCoy pleaded with Admiral James T. Kirk to take him home and "climb the steps of Mount Seleya," much to Kirk's confusion, considering that McCoy was fully Human. After Kirk realized that McCoy was carrying Spock's katra and brought both individuals to the mountain (complying with instructions from Sarek, Spock's father), venerable high priestess T'Lar supervised Spock's fal-tor-pan ceremony at the altar on Mount Seleya. (Star Trek III: The Search for Spock) Spock privately underwent final memory testing near the mountain but he and his crewmates left Vulcan three months after their arrival, in 2286. (Star Trek IV: The Voyage Home)
Mount Seleya wasn't in an initial story treatment that Harve Bennett wrote for the third Star Trek film (dated 16 September 1982, while the film had the working title Star Trek III: Return to Genesis). However, it was featured in the first draft script of Star Trek III: The Search for Spock (dated 23 March 1983), in which it was initially described as "a temple complex on a high, forbidding promontory." A bracketed note then instructed the reader to "see ILM sketches." Later in the same script, the "Temple area" was used for the landing of a Starfleet-commandeered Klingon Bird-of-Prey bringing Spock to the area. No precise description was given for the journey from the landing site to the place used for the rejoining of Spock's katra with his body. That destination was referred to as a "ceremonial altar", further described thus; "The altar itself is at the foot of a giant silo-like structure. In an open air amphitheatre ringed by Stonehenge-like rock structures." A bracketed note then advised, "See ILM sketch."
An important aspect in the conception of Mount Seleya was that Leonard Nimoy wanted its altar to be on a raised platform, so that the Starfleet officers bringing Spock to the mountain had to first land their Bird-of-Prey in an area separate from the altar. This was for a variety of reasons, not the least of which was that adding the ship to shots of the temple would have been expensive. Nimoy also conceived of the route to the high altar. "Leonard wanted a narrow passageway, a thoroughfare, for dramatic purposes," said Industrial Light & Magic art director Nilo Rodis. (Star Trek: The Magazine Volume 3, Issue 8, p. 55)
The ILM art department produced many different conceptual illustrations for Mount Seleya's altar. For instance, fellow art director David Carson created sketches of the altar and drew a series of storyboards showing the Bird-of-Prey land near Mount Seleya. (Star Trek: The Magazine Volume 3, Issue 8, p. 55) Another ILM employee, matte artist Chris Evans, painted the mountainous scene with craggy cliff tops. (Cinefantastique, Vol. 17, No. 3/4, p. 50) A separate view of the clifftop altar incorporated the concept of a large ceremonial fire, though this idea was evidently not used. (Cinefantastique, Vol. 17, No. 3/4, p. 70)
The initial view of Mount Seleya in Star Trek III had to establish the area's geography at a glance. "From my experience, you have tops maybe 15 seconds of that shot," Nilo Rodis explained. "The logistical and dramatic implications of those 15 seconds has got to be very clear and very simple. It cannot be cluttered otherwise it won't stick in your memory. To get to that one design, I'm embarrassed to say that I probably spent days, if not a week, trying to come up with a simple design so that it was memorable." The final design for the clifftop temple was also as minimal as possible, helping focus the film's emphasis on the events taking place on the mountain rather than on geographical detail. Rodis noted, "It had to be simple and uncluttered." (Star Trek: The Magazine Volume 3, Issue 8, pp. 55 & 61) The final version of the altar set was designed by art director John E. Chilberg II. (Cinefantastique, Vol. 17, No. 3/4, p. 70)
Decorating the altar
The unusual, large "V" symbol towering over the altar was designed as a stylized version of the Vulcan salute. (Cinefantastique, Vol. 17, No. 3/4, p. 74; The Making of the Trek Films, 3rd ed., p. 54) In a concept painting of the statue, the symbol was more clearly a representation of a hand making the salute. (Star Trek: The Magazine Volume 3, Issue 8, p. 55) John Chilberg illustrated the original concept sketches of the symbol. "The edifice was designed to have a utilitarian sculptural effect," recalled set decorator Tom Pedigo. "It was intended to look as if it was sculpted out of stone." The statue, ultimately measuring twelve foot high, was actually built out of plaster and Styrofoam. (Cinefantastique, Vol. 17, No. 3/4, p. 74; The Making of the Trek Films, 3rd ed., p. 54)
Not only did this colossal construction resemble a Vulcan salute, but so did a much smaller sculpture that was positioned at the center of the edifice. In addition to the altar featuring a gong similar to one in "Amok Time", the entryway of the altar partly consisted of a large fiberglass dome that was actually reused from the Genesis cave in Star Trek II: The Wrath of Khan. (text commentary, Star Trek III: The Search for Spock (Special Edition) DVD)
Realizing the mountain
Choosing what to show in the background of the altar was problematic. From such an elevated vantage point and with other mountains only scattered in the foreground, the only thing that would realistically be visible in the background would be sky. Set designer Cameron Birnie remembered, "The argument we had was that if all you could see was sky, how'd you know you were high up?" (Cinefantastique, Vol. 17, No. 3/4, p. 75; The Making of the Trek Films, 3rd ed., p. 54) Nilo Rodis noted, "You wanted to show that you were up in the sky, but in reality you were up in the mountains." (Star Trek: The Magazine Volume 3, Issue 8, p. 63) One solution was to try experimenting with the horizon line. (Cinefantastique, Vol. 17, No. 3/4, p. 75; The Making of the Trek Films, 3rd ed., p. 54)
Illustrator Tom Lay was assigned to work from ILM's concepts for the altar set and devise what would be in the background. He made concept paintings of the area, the first of which was a small illustration which demonstrated the scene at night. (Star Trek: The Magazine Volume 3, Issue 8, p. 62) Lay outlined which segments of the painting would have to be converted to backdrops, and drew up the correct scale. He reminisced about the painting, "Everybody loved that [....] They said, 'Well, OK, except paint it for daytime and we'll light it for night.' So I did that, and there were a few other changes." (Star Trek: The Magazine Volume 3, Issue 8, p. 63) In fact, the backing evolved through four sketches and was blown up to a large scale. (Cinefantastique, Vol. 17, No. 3/4, p. 78) Lay concluded, "The changes were done accurately but, by the time they saw it in a finished size, they couldn't even recognize it!" (Star Trek: The Magazine Volume 3, Issue 8, p. 63)
The set for the altar was constructed on Paramount Stage 5. (Cinefantastique, Vol. 14, No. 3, p. 11) An extremely expensive backing, Tom Lay's eventual design was painted on the stage, encompassing 250 degrees of the set. (Cinefantastique, Vol. 17, No. 3/4, p. 75; The Making of the Trek Films, 3rd ed., p. 54) However, the enormous backing had a clear horizon line dividing the sky and the surrounding mountains; essentially, the horizon line was too high, making the temple seem as if it were in a crater or a valley. (Star Trek: The Magazine Volume 3, Issue 8, p. 63; Cinefantastique, Vol. 17, No. 3/4, p. 75; The Making of the Trek Films, 3rd ed., p. 54) Once Leonard Nimoy, agitated with the design of the backing, called Nilo Rodis down to Los Angeles, Rodis viewed the problem for himself. He fortunately managed to come up with a quick and easy solution. "I said, 'Just get rid of the backing, and have the director of photography light it as if it is sky.' And that's exactly what they did.'" A new, orange cyclorama backing was painted like the Vulcan sky by J.C. Backings. In an effort to give some life to the backdrop and make it seem as if it was glowing brighter than an ordinary painting, the revised backing was lit from both the front and the back. (Star Trek: The Magazine Volume 3, Issue 8, p. 63) Nimoy was still nervous about the backgrounds of the Mount Seleya set, though, owing to its minimalist nature. "I had a conversation with the photographer," related Nimoy, "and I said, 'Look, make it go out of focus,' because what it looked like was a painted piece of canvas back there. So, you cross your fingers and hope it works, you know?" (audio commentary, Star Trek III: The Search for Spock (Special Edition) DVD/Blu-ray) The unused, more detailed backdrop was incorporated elsewhere in the film's depiction of Vulcan. (Cinefantastique, Vol. 17, No. 3/4, p. 68)
Since altering the lighting on the large set between a night and dawn setting was potentially a major undertaking, all the night scenes were filmed together and the dawn scenes followed. This prevented the production crew wasting time and money on changing the lighting more often than was necessary. (text commentary, Star Trek III: The Search for Spock (Special Edition) DVD)
Ultimately, several matte paintings, provided by ILM, were used to depict Mount Seleya, as seen from a distance in the film. (Star Trek: The Magazine Volume 3, Issue 8, p. 27) One such painting – a view of the mountain at dawn – is shown on screen for fourteen seconds, an unusually long duration for a static matte painting to remain on screen. (text commentary, Star Trek III: The Search for Spock (Special Edition) DVD) Kenneth Ralston, the film's visual effects supervisor, was wary of the shot almost serving as too much of a reminder to the audience that the view was an illusion. He commented, "I think they hold on [it] longer than any matte painting ever. It still holds up; but boy, I'm clawing at the arms of my seat saying, 'It's too long, too long!'" (Cinefex, No. 18, p. 52)
Although it was also planned for an ILM matte painting to have extended the set for the temple, this was not ultimately the case and such a painting was never used. (Cinefantastique, Vol. 17, No. 3/4, p. 82) Neither was footage of a procession carrying Spock's body up the mountain, which included the interior of the clifftop Hall of Ancient Thought, which was ultimately left unnamed in the film. (Star Trek: The Magazine Volume 3, Issue 8, p. 60)
A "large, time-worn" tapestry of Mount Seleya was referred to in the first draft script of ENT: "The Andorian Incident" (which had the working title "Incident at P'Jem"). It was to be shown on-screen, covering an entire wall in a so-called "radio room" in the catacombs of the P'Jem monastery. In the script's stage directions, the tapestry's view was described thus; "A ritual altar overlooks an eerie volcanic landscape." The teleplay's dialogue stated about the tapestry, "It is from the time before Surak. The Altar of C'thia. The Well of Truth." However, the Mount Seleya tapestry was not referred to in the episode's final draft script, and doesn't appear in the final version of the installment. The tapestry hid a metal door, which led to an underground spy station, otherwise known as "Memory Alpha".
In the first draft script of ENT: "Fusion" (which had the working title "Equilibrium"), V'tosh ka'tur Szon angrily accused T'Pol, while she was refusing to let him initiate a mind meld with her, of "acting like one of those old fools who live atop Mount Seleya" (apparently a reference to the Vulcan Elders).
In reality, Mount Seleya definitely provided the name for the Vulcan ship Seleya. (ENT: "Impulse" text commentary, ENT Season 3 DVD) The mountain was originally to have featured as a prominent setting in Star Trek: Enterprise's Vulcan trilogy (comprised of the episodes "The Forge", "Awakening", and "Kir'Shara"). A major battle between armies would have taken place on Mount Seleya in the conclusion of that arc, although this idea was abandoned, since it was considered to be prohibitively expensive. (Cinefantastique, Vol. 37, No. 2, pp. 36-37) Mount Seleya was also rumored to appear in the episode "Kir'Shara", prior to that installment airing.
The design of Mount Seleya influenced a pair of computer-generated matte paintings in the remastered version of "Amok Time", created to help show the planet of Vulcan in a more expansive way than that episode's original version does. (Starfleet Access for "Amok Time", TOS Season 2 Blu-ray)