A so-called "Iceberg" city is a type of city commonly found on Th'ega controlled worlds. Iceberg cities are normally built in the oceans of these worlds, but the city on Halka is an exception to this rule. These cities are likened to icebergs because only a small portion of the entire city is visible on the surface and the underwater levels are completely hidden.
Most cities of this design extend to the ocean floor of the planet they're on, however some are smaller. The average height for an iceberg city is 17 kilometres, with an average diameter of 2 kilometres at their widest. The typical design is similar in shape to a spinning (tractricoid) top, though most cities don't have a spire that extends above the surface. The largest iceberg city is Li'ion on Kavla. It supports as many as 1.3 billion people, 99.7% of whom are Th'ega, with the rest being a mix of Humans and Xa'Thin.
The first iceberg city was designed by Vell'ae Ikrael, a Th'ega architect who was well-known for her unorthodox designs, in 193,301 CE. A decade later, the Central Kavlan Government approved the construction of one of these cities. To the CKG, it was merely an experiment which was likely to fail due to the ridiculous costs involved. However, the city quickly paid back all the funding it had been given and became the economic hub of Kavla. Later, Vell'ae would design the Central Kavlan Parliament building on this city. Originally, the city was called Proch'an ("God of Peace" in Kail) but soon it was changed to Vall'ae in honour of its designer. Ikrael died in 193,411 CE at the age of 165 standard years (573 Kavlan years), but her legacy lives on in the form of the cities. In 198,381, a petition was put forward to rename then-Xani'en to Ikrael. The petition was approved and the planet was officially renamed in the architect's honour.
As mentioned before, the cities bear similarities with both icebergs and tractricoid tops. The general design is a hemisphere above water that gradually sloped inwards to form a sort of spire. Most iceberg cities are tiered, but these aren't divided by class, race or wealth, contrary to popular belief. For example, the very bottom of the underwater spire is no different in terms of quality or wealth as the very top layer. The only difference is space, meaning fewer people live towards the bottom and more people live in the top hemisphere.
The cities are designed to float in case the super-strong cables that anchor them break apart, but most cities actually extend to the seafloor and are anchored by more durable materials. Li'ion is a prime example of this, with a height of 37.47 kilometres. Some cities are planning to go as far as 40 kilometres deep on Raelka and have even secured funding from the Federation.