Laputa is the setting of the latter part of Laputa: Castle in the Sky. As the name of the film suggests, Laputa is an immense castle floating on an island in the sky. The opening credits showcase the development of the technology by which this is possible.
The film's protagonist, Pazu, has a photograph his father took when he glimpsed the almost mythical place. Because his father died still trying to prove Laputa's existence, Pazu dreams of finding it and proving his father right. Along with Sheeta, a young girl who is the rightful heir to the throne of Laputa, Pazu eventually succeeds in his goal. However, thanks to the pursuit of Captain Dola and her gang of air pirates, and government agent Colonel Muska, and the subsequent events that take place there, much of the structure of Laputa is destroyed. The remaining, natural part of the island floats away to drift over the Earth undisturbed.
Laputa was once the heart of a very advanced civilization which utilized the power of a giant crystal of the element Aetherium ("Volucite" in the original Japanese and Streamline English dub) located within the island. In addition to making the entire island float, the crystal gave the Laputians the technology to create sophisticated robots and weapons. However, eventually the Laputians chose to leave the island; Sheeta speculates they came to realize the importance of maintaining their connection to the Earth below.
The Kingdom of Laputariches, or "Laputa", was built when a great technological civilization over 700 years ago (the one in the story's present-time is the second, as depicted by the film's opening) thrived, by a people who fled to the sky out of hatred for the wars of the Earth. In this time, Laputa was a pinnacle of the civilization's technology, dominating the skies in a hegemony of other aerial kingdoms. Unlike these other kingdoms, which relied on rotors, Laputa maintained its airborne state by way of the element Aetherium. For a time, the kingdom prospered. However, after the civilization reached too high an altitude, the Laputians lost their vitality, and the population gradually declined, until they died out as a result of a strange disease that broke out abruptly around 500 BCE. The ancient Greek philosopher Plato is said to have made note of this history in his lost geography On the Heavens, the minimal surviving knowledge of which inspired the Laputa of Jonathan Swift's Gulliver's Travels. [2Legend has it that some of the Laputians, including the royal family and some of their subjects, abandoned the city at this time, hid themselves and lived on, but the details of this are unclear. Laputa was deserted, left only to the care of robots that waited for the return of their king. Over the years, the territory crumbled, and now only part of it wanders through the sky; moving with the westerlies as a constant low-pressure system that hides it entirely from view from the ground.
Laputa's existence has long been a myth because it was mentioned in the satirical novel Gulliver's Travels . Therefore, no one could imagine that there really was a highly developed culture that could lift entire cities into the sky. The families whose ancestors or they themselves once lived in Laputa were also silent. Sheeta would not have known about the existence if Pazu and Muska had not told her about it. Pazu's father personally saw and photographed Laputa. But nobody wanted to believe him because the plot of the book Gulliver's Travels is only fictional.   Muska, however, knew about this place and was waiting to find evidence. This was provided by a robot that fell from the sky. 
Once upon a time there were people who tilled their fields with cattle in the country. They aspired to circle the sky like birds. So they built many different flying machines. Some were successful, others less. Then came industrialization and they dug into the earth. They dug deeper and deeper than people who did today. Because they wanted to recover neither iron nor tin, but Volculite . 
The flying machines powered by Holozite could be made much larger than previous of their kind. Eventually they reached the size of a city. But the goddess of the wind blew incessantly from time immemorial. So it came as it had to come, the floating island cities crashed and the people gave up the dream of soaring in the air.  But the dream of flying lived on in people - one island city remained: Laputa.
Laputa hovers in the sky and does not move, which is rather unusual for an island city. To find the island city, Sheetas is flying stone needed. After she has spoken the “magic formula”, the stone lights up and shows her Laputa's whereabouts with a ray of light. 
The floating island lies in a cloudscape, which is also known as the dragon's cave (Japanese 龍 の 巣, ryuu no su ). The cloud masses draw nearby flying machines towards them. If the machine is close enough to the vortex, lightning bolts in the form of kites flash around the machine and then form columns to show the way to the landing platform. 
Pazu says to Sheeta after they have landed that Laputa can only be reached with the flying stone  . However, this does not explain how Pazu's father was able to get to Laputa  . Perhaps he also had his own flying stone with him, which was never seen in the film.
In the center of the island there is a tree (jap. 大樹, taiju ) in a greenhouse. The crown of the tree protrudes above the greenhouse, which consists of white round buildings. Moss-covered maintenance robots , which appear to be defective, lean against the tree , according to Sheeta. 
Two tablets with cuneiform writing are attached to the tree. One of them is suspended from the tree and the other is on the ground. Since there are flowers on the board, it seems to be a tomb. A few steps away from the tree it is rich in vegetation and this forms a contrast to the motionless robots. Tall trees grow here in which chirping birds build their nests.  There are also graves here that are looted by Muoro's people  .
Below the tree is the dome that covers its roots. There is the Volculite crystal (Japanese 黒 い 石, kuroi ishi ), which lifts Laputa into the air. The crystal stands in a pond, which is crossed by the roots of the tree. A tablet with cuneiform writing is attached to the crystal. Muska goes with Sheeta's stone on the board and can control so the individual modules. 
For example, he was able to lure Muoro and his men into the viewing platform and fire the Indra arrow cannon from the Ramayana to demonstrate their power. To do this, he uses his to extend spikes out of the dome. The weapons-fire, which was generated by electricity, hits the sea and leaves behind a mushroom cloud. According to Muska's testimony, the cannon destroyed Sodom and Gommorah . Ramayana is an Indian national epic. Indra is a Hindu deity, specifically that of fire and thunder, an apt reference. [8th]
In the control center, Muska, and presumably previous rulers, can access the high-technology electronic repository containing all of Laputa's secrets and knowledge, in turn contained within the modules, as well as control the robots, project his voice through loudspeakers throughout Laputa and make holograms appear. Since Muska can control the individual modules, he was able to dissolve the floor of the viewing platform and thus let the soldiers fall into the depths. The dome is criss-crossed with dark corridors, the walls of which have been carved in straight lines. Some of them are guarded by robots. Not far from the holocite crystal is the coronation hall. [8th]
Sheeta's stone is required to get into the dome. The entrance is on the ring of the island. Muska feels for the king's emblem and runs the flying stone over it. As if by magic, the entrance to the dome clears. Between the entrance and the crystal is a room with floating cubes. According to Muska, his agents must remain in the room of the dice because only members of the royal family can enter the location. However, Pazu was able to move through the dome without Muska's knowledge. [8th]
Outside the center on the surface there is a huge garden that is tended by robots. There is rich vegetation here, even if the grasses and ponds have their permanent place. 
Birds, fox squirrels , four-eyed beavers, multi-winged dragonflies and the prehistoric fish Dunkleosteus live here. The latter live in ponds, the small frames of which are rectangular or round. All ponds are connected by an underground lake. By looking into the lake from the edge of the pond, the depth of the lake cannot be seen. People have dwellings in the lake.  Paved paths, stairs and pillars point the way to the landing platforms.
The outer ring consists of columns, walls, bridges and stairs. They are used to land on Laputa. Small flying machines can land on pillars, while larger machines dock against the wall. When landing on Laputa, guests are usually greeted by a robot.  The outer ring and the dome serve to prevent Laputa from floating into space.
After Sheeta and Pazu have pronounced the formula of annihilation, the dome and the outer ring crumble. The combat robots that are not responsible for the care of Laputa are also deactivated and fall apart. The holocite crystal flies up to the tree in the center. Laputa loses weight and floats towards space. Officially, it was mentioned later on Japanese television in order to calm the children's conscience that Laputa is not in space, but is still in a celestial sphere where the fox squirrels can survive.
The Laputian population at that time was extremely technologically advanced, far beyond modern knowledge, hence Muska's obsession with the edifice . For example, the ancient people managed to build intelligent robots that could also fly. The robots also had no shortage of weapons. Apparently the residents had been at war, otherwise they would not have attached a cannon to Laputa. [8th] An alternative theory exposed by Lucita and Romuska at various points, was that Laputa was used as tool of domination, an apocalyptically powerful weapon would certainly help keep people below in line.
Furthermore, unique among their technological capabilities was the residents were able to process Aetherium and create airworthy material from it. With the help of a large crystal it was achieved that an island city could be lifted into the air.
The population were not poor by any measure certainly, as the island housed chambers full of treasures. 
Laputa apparently ruled a (seemly absolute) monarchy as there was a royal family whose descendants are Muska and Sheeta. While Muska's family has kept the knowledge of Laputa for 700 years, Sheeta's family has forgotten the place in question. They just passed on the flying stone and activation codes. The coat of arms of the royal family is depicted on the stone .  When Sheeta and Pazu reached the island, they only encountered a single robot who apparently took care of everything  . In addition, many animals still lived there. There were no more people living there. Apparently, the fall was of Laputa civilization caused by a man-made disaster, similar to Plato's story of what happened to Atlantis  .
The language of the Laputans is spoken and written. The writing is a cuneiform. A character consists of vertical, horizontal and diagonal notches. A character can mean a word or a phrase. The following sentences appear in the film:
Activation of Sheeta's flying stone
Rite ratuba rita urus area rosunaru netoriru
Help us to awaken the Holy Light from the primeval times of heaven
Sheeta's full name, Lucita Toelle Ur Laputa Lucita, the true Queen of Laputas Ur means king or queen Toelle means truly
Muska's full name Romusca Palo Ur Laputa,
Romusca, the (palo) king of Laputa
Royal coat of arms
The royal coat of arms can be seen for the first time on Sheeta's flight stone  . Later, the coat of arms reappears in the film to mark elements of the plot (and so that Muska can find his way to the command center). The coat of arms appears on a combat robot that was stored in the Tedis fortress . On the city island, Muska discovered the entrance to the dome by scanning a wall for the coat of arms and then holding the flying stone in front of it