The Mobile City is the capital of Crestoria. It is a marvel of postartistic engineering.
The city sits on an enormous rectangle-shaped raft, its smaller side 1300 metres long while the longer side is 2600 metres long. It can unfold into 8 isosceles triangles connected at their edges it it needs to traverse a thinner section of river.
The floor is made primarily if varnieshed muirapixuna wood, which is durable and only needs to be replaced every 35 years (the floor is replaced in sections). This flooring stands on many modular titanium beams, which are not bolted nor welded, but fit like jigsaw pieces. The beams are hollow and filled with air, but the whole raft is sustained by many double-layer plastic containers, also filled with air. At the baricentre of each triangle there is a large titanium ballister. Each platform has many holes which allow for communication between air and water, and facilitate maintenance on each region.
The raft can move along the current or fight against it. There are many sails and turbines along the city, so the raft may follow the wind or be moved at the cost of electricity. Before the turbines were implemented, slaves were forced to row the whole raft and its many tons. Under each platform is an anchor which can be shot.
Many buildings fill the space above and under the raft. They vary in size and were built so the city has a particular symmetry. On one of the innermost triangles is the Presidential Palace (as per the image), a pentagonal building ornated with bamboo beams and illuminated by fireflies. Around the palace's plaza are the smaller, one-to-two story buildings that are inhabited by Fairies and by smaller Zoans. Then comes a region of the largest buildings, often many stories tall; or one story tall, but large enough to house a Barophore.
At the hypotenuse of each triangle is a portuary region which also features cannons to protect the city. At the cathets there are defense towers where archers perch, but also a few inversible piers for when the city unfolds its platforms.
The central region of each platform is different from that of the Palace District. The one adjacent to the Palace Platform's hypotenuse only features a town of tiny houses similar to the ones near the Palace itself. The four platforms which form the longer sides of the city have industries and silos. The other outer platforms have a religious district and a market, respectively.
The underwater towns are smaller than the ones in the air. There is a region of the palace that stretches underwater, and around it is a purely military complex, where harpoons protect the plastform from underneath.
Around the ballast of each platform (besides that of the Presidential Palace) are the larger houses, though not as large as those above the water, since Barophores are air-breathing and the largest shark Zoans do not often venture into fresh water. As one nears the edges of the platforms, the houses become gradually smaller. The edges are again guarded by harpoon cannons. Two of the triangles (the ones on the longer sides, on the same square as the palace) feature industrial complexes again.