Sol City is a floating city in Boktai: The Sun is in Your Hand. It is floating high above Istrakan, and is now abandoned. It was once populated by the Solar Children, people of the tribe of the sun, but they all disappeared...
Though long since abandoned, the city is still navigable (Though only somewhat) and operating. The city moves through the sky via Solar Power, and in the event of strong sunlight will begin creating air current to push itself through the sky. In Boktai, the air currents can also push the player over the edge, so it's best to cover the Solar sensor until Django get to the main part of the city. The city still has it's gardens of exotic flora, as well as Fauna.
Though the mysterious inhabitants of the city are long gone, Undead now roam the city, as well as the petrifying Cockatrees. The only other thing here that isn't Undead is the Immortal controlling them, Carmilla the crying banshee.