The city is a constitutional monarchy, with an economy dominated by tourism and precision machinery. Politically, it does not appear to be part of the United Federation, or under the protection of the Guardian Units of Nations.
Reigning monarchs apparently eschew the title "King" or "Queen", and Soleanna's sovereign is generally known as 'Duke' if male or either 'Duchess' or 'Princess' if female. The small nation is apparently wealthy and prosperous; with its urban environments bearing resemblance to modern Mediterranean cities. However, Soleanna is shown to possess highly advanced technology, as is evident in Aquatic Base, a research lab underneath the ancient Royal Palace (located in Kingdom Valley).
The city worships a deity known as Solaris, "The Eternal Sun God", who is honored during the "Festival of the Sun". Soleanna's sovereign during the events of Sonic the Hedgehog is the young Princess Elise, introduced while presiding over this ceremony. In the game's timeline, the ancient castle that used to house the royal family in Kingdom Valley has been abandoned after the Solaris Project accident. The new castle is on an island off of Castle Town near New City – although it is unclear if this remains true in the new timeline after the game.
Soleanna New City is an Adventure Field in Sonic the Hedgehog (2006). One of the three overworld areas in the game, this area is an important hub for Action Stage access, Town Missions and hidden medals.
The commercial and industrial center of Soleanna, the New City is decidedly more modern-looking than its counterpart Castle Town. Tall buildings and wide roads have taken over from rustic boutiques and cobbled footpaths; there's even a modern port area with warehouses and ship-loading cranes, and the headquarters of the Rimlight Corporation can be found here. There are a couple of G.U.N. agents quietly operating here, as Shadow the Hedgehog can discover. The New City isn't all business, however, as it also hosts Soleanna's marina, where colorful yachts crowd the jetties.
Festival of the Sun
Soleanna, being a cultural center, is the holder of numerous celebrities. The most famous event is known as the "Festival of the Sun". The sun has been always sacred in the city, it is an important part of the culture of Soleanna, and the citizens give thanks for the sun by honoring the traditional sun god, Solaris.
Crisis City and Paradox
There are some hints that Crisis City is, in fact, Soleanna in Silver's future. The ruined buildings bear physical resemblance to those seen in downtown Soleanna during the main timeline. Further indications come in the form of Eggman's still-active base, and Elise's apparent hallucination of Soleanna in flames, with Iblis in the center, during the opening cutscene of Sonic's story.
In other media
Soleanna is a location mentioned in the Archie Comics' Sonic the Hedgehog comic series and spin-offs. In this media, Soleanna is a Human/Overlander settlement in Eurish, created as a part of the Hidden City Initiative, and a city-state of the United Federation and is ruled by Princess Elise.
- The eagle is the symbol of Soleanna. This is exemplified by the medals marked by an eagle, the birds that appear in the Action Stages, and Solaris' head which is shaped like an eagle.
- During the scene in Sonic's story after they come back from the future, Sonic picks up a newspaper. If you look closely at it, it's called the Daily 'Soreana'.
- In the nighttime version of Sonic Unleashed's Skyscraper Scamper there is a neon sign reading "Soleanna Hotel" in yellow.
- Soleanna is based on and has a similar style to the water city of Venice, Italy, which may be how Silver got his original name.
- Soleanna is well known for its delicious food, such as their juicy apples and the Freight Sandwich.
- The people of Soleanna celebrate many festivals, including The Soleanna Apple Festival, The Water Target Tournament, The Ring Race, and most importantly, the Festival of the Sun, where they pay honor and tribute to Solaris.
- There are actually no roofs on the skyscrapers in New City. If one were to enter as Sonic and use the Sky Gem Custom Action, they could see for themselves. For this to work, one would have to throw a Gem at an angle at a building, causing Sonic to fly upward at high speeds. If the player tries to fall down on the nonexistent roof, they will fall through the building, and eventually out of the bottom of the area.
- Ironically, the Solaris Festival, held in honor of the sun god Solaris, is held at night rather than during the day. Also, Soleanna is the city of water, but their god is a fire creature.
- Most of the general socioeconomic information about Soleanna comes from Rouge's explanation to Shadow after they escape from White Acropolis.
- We see no GUN mechs in Soleanna at any point during the game, and the citizens rely on Sonic & co. to repel the invasions of Eggman's forces. However, GUN "agents" are shown operating (without much discretion) in downtown Soleanna during Shadow's story, so it seems likely that Soleanna is at least an ally or client state of the United Federation.
- Although the deceased Duke of Soleanna is referred to almost exclusively as a "Duke" throughout Sonic '06, Rouge does refer to him as "the former king" during a conversation in Kingdom Valley. The title "Queen", however, is used in reference to Elise by her father; become a strong queen who won't cry no matter what happens.
- The monarch may still be the Duke of Soleanna instead of his daughter Elise, since the Solaris Project never exploded and the Duke was accordingly never killed. However, Elise is still seen presiding over the Festival of the Sun in the revised timeline; as such, the ruler of Soleanna in the canonical history is unknown.
- Sonic Team. SONIC THE HEDGEHOG (Japanese). Action Stage: Kingdom Valley. Sega. Retrieved on 22 August 2016.