Dynamo City is a world within it's self. It is extremely technologically advanced. The city's sole purpose is commerce. The city has the size of the biggest metropolis of planet Earth and it is organized like this as well, with a core center, work-oriented and a suburbia, Tent City which looks like slums.
The city is an omni-energy absorbing complex. This means all energies are taken and converted to the city's central battery upon entering the city. This includes solar, chemical, electrical, ionized or cosmic energies. When Silver Surfer entered his Power Cosmic was stripped of him.
The city is controlled by artificially intelligent robots that have strict law systems. For example, private possession of any energy is a felony since all power belongs to the municipal government.
The court system is run by robots and unfair trails are common. After a person has their fourth law broken they are sentenced to death. They use a termination chamber to transport the guilty into space for a cold death. The controller of the city is called the Great I, but this creature merely controls the city's operations. Greedy bureaucrats actually control the masses.
Citizenship in Dynamo City is extremely difficult to get. Some come for dreams of becoming rich and others are just trapped there because of the exit fees. This undesirables live in Tent City, a camp outside of the city.
Thanos is a citizen of Dynamo City and this is why the Silver Surfer was brought to one of Dynamo City's tribunal to be judged by P-UZD-C.