Although sky cities have been sighted for centuries the subject still unknown to most people and even now days with the advance of technology cities in the sky still not broadly divulged on the internet hence why Paradox choose the matter to be one of our first posts.

There is no accepted scientific explanation for such vision but all in all the sighting of sky cities is also not accept even by people that explore the paranormal. For those that indulge in the subject the matter may have different plausible explanations for example:

Some believe that the sighting may be a mirage an atmospheric distortion and an optical illusion. Light from an object may be bent (refracted) or reflected by air, and the mind of the beholder is liable to see something which is not what it appears to be. Some believe that they are “doors” to a different dimension on time and space and were those cities are real. Others believed that they are mirror images of actually cities represented on the sky by some freak natural phenomenon still not comprehended by “man animal”. Whatever is the case herewith is a small compilation of some of those appearances throughout history.

                           1- In the Transactions of the British Association for the Advancement of Science of 1847, Dr. D.P. Thomson reported that "during the exhibition of a panoramic model of Edinburgh, in the Zoological Gardens at Liverpool, on Sept. 27, 1846, about 3 P.M., an erect image of Edinburgh, depicted on the clouds over Liverpool, was seen by two residents in the Great Park at Birkenhead, for a period of forty minutes." Edinburgh is about 325 kilometres north of Liverpool.

                            2- Another sighting was reported in the London Times as having occurred on July 28, 1846, at 3:30 A.M., near Stralsund (then part of Pomerania and now Germany). During a short walk from the city on the Baltic shore, witnesses saw in a pale blue light the image of Stralsund looming over the Isle of Rugen on the opposite shore for a period of 15 minutes. The image was clear enough that details of the facade of the Gothic church of St. Mary could be "distinguished with ease."

                             3- An American prospector, Mr. Willoughby, claimed he heard an Indian legend of a city appearing in the sky each summer near Mount Fairweather, on the Alaska-Yukon border. Mr. Willoughby said he first saw the mirage in 1887 and offered a photograph as proof that the phenomenon was real. In 1889, the New York Times reported that the city in Willoughby's photograph had been identified as Bristol, England. This story and the photograph were included in a later edition of Miner Bruce's Alaska.
Willoughby's photograph
                             4- Two other cities were said to have been seen over the Muir Glacier in Alexander Badlam's Wonders of Alaska. Badlam reprinted Willoughby's photograph, which depicts a view of a city from a hillside with house fronts and church steeples clearly visible; and, if not claimed to be photographed in Alaska, it could readily be accepted as a photograph of Bristol. However, a second photograph is presented with an African or Asian city superimposed upon another of a glacier. Badlam writes that the photographer had captured the mirage's image by aiming his camera into a pan of quicksilver and that the city seen in the sky was believed to be sunken in the waters of the bay in front of the glacier. The third city was supposedly sketched from a photograph, but the fanciful spires and towers of the artist more closely resemble the looming mirages of Arctic icefields or the Fata Morgana of the Straits of Messina than anything else.
                       5- One of the members of the Duke d'Abruzzi's expedition to Mount St. Elias, C.W. Thornton, told Miner Bruce he saw what looked like a city in the summer of 1897; L.B. French was quoted by the New York Times in 1889 as seeing houses, streets, and large buildings, either mosques or cathedrals, near Mount Fairweather; and, a correspondent of London's Weekly Times and Echo returning from the "Yukon Goldfields," saw a city in the sky in June of 1897 and wrote: "...whether this city exists in some unknown world on the other side of the North Pole, or not, it is a fact that this wonderful mirage occurs from time to time yearly, and we were not the only ones who witnessed the spectacle."
                                 6- The same phenomenon exists in Ireland. The "Duna Feadhreagh," or fairy castles, have long been reported. On the coasts of Antrim, Donegal, and Waterford, enchanted islands have been seen rising from the depths into the skies. The Chronological Description of Connaught, written in 1684, says: "There is, westward of Arran in sight of the next continent Skerde, a wild island of huge rocks; there sometimes appear to be a great city far off, full of houses, castles, towers, and chimneys, sometimes full of blazing flames, smoke, and people running to and fro. Another day you would see nothing but a number of ships, with their sails and riggings; then so many great stakes or reeks of corn and turf."

                               7- At Rathlin, in 1817, a green island was believed to arise out of the sea every seventh year upon which could be distinctly seen people "engaged in various other occupations common to a fair."
                                8- At Youghal, a walled town was seen distinctly in October of 1797. By June of 1801, the mirage had grown into an unknown city with mansions and forests behind.
                                9- Such marvels were recounted by Dr. Thomson in his Introduction to Meteorology and before the British Association for the Advancement of Science in 1852 by Mr. M'Farland (who had witnessed a fairy island arise from the ocean off Portbalintrea in June of 1833). Sir Charles Lyell, the distinguished geologist, wrote of seeing a mirage of Toronto in the sky over Lake Ontario during his second visit to North America.

                                10- In the British science journal Nature, accounts of mirages in Scandinavia, such as the one here in May of 1882, may have helped prompt an earlier acceptance of tales from a sourdough in Alaska and the legends of the Irish:

                                11- The frequent observations of the mirage in the south of Sweden is  very remarkable. From time to time we are told that whole landscapes, cities, and castles, with moving objects, have been observed reflected on the sky for hours, and we again learn that a similar display of the forces of Nature was seen one afternoon last month over the lake of Orsa, in a remote part of Dalcarlia, lat. 61 degrees, which is stated to have reflected a number of large and small steamers, as if plying on the lake, and from whose funnels even the smoke could be observed to rise. Later on the scene changed to a landscape, the vessels now taking the form of islands in the lake, covered with more or less vegetation, and at last the mirage dissolved itself in a haze. The phenomenon, which lasted from 4 to 7 o'clock, is said to have furnished a most magnificent spectacle.

Such phenomenon requires closer examination....