The Babylon 5 station is technically a space colony, meant to be partly self-sufficient with regard to air and water and home to a number of permanent residents as well as an embassy. It is best described as a cylinder with a sphere of similar radius attached to the 'front' of the station, which contains a docking platform, similar to the one on the spacestation in 2001: A Space Odyssey, which can be said to be the major inspiration for much of B5's designs.(see Omega Class Destroyer and compare to the Alexei Leonov in 2010: Odyssey Two) This forward section houses the docking bays and receiving area and the forward Command and Control. The central section contains, toward the front, shopping areas, markets, bars, restaurants, Zocolo and garden space. The middle of the cylinder is given over to quarters, for humans and non-humans alike, which means entire sections given over to different atmospheres and atmospheric pressures. Also, this area houses a number of Medlabs, which serve as hospitals and as staging grounds for xenobiological research for human doctors. This section is the largest, volume-wise, of any of the sections. From here, continuing to the back, is the section that spins the station and houses the massive solar arrays that supplement the station's power supply. The final inhabited part of the station is the Down-Below, a sector given to industrial work and air/water recycling that quickly became the area where poor people, looking for work came and found none. The last spinning part of the station is the Fusion Reactor housing. The sector of the station that does not spin is mostly a cargo processing area, defense net support and the mechanism that spins the station.
The station is spun because the Earth Alliance did not have access to gravetic technology at the time of the station's construction. This gravity has been calculated at ~.33g on the ground of the garden area of the station, thus higher in sections further out. The station was designed along the lines of the first three Babylon stations, which were ambitious projects, but contained a single spinning section, like that of EA Asimov Transports and Omega Destroyers. The fourth station's design used a spin/anti-spin design that would use a second section spinning in the opposite direction to balance the station automatically, instead of requiring frequent rebalancing thrusts and large gyroscopes. This design would also have allowed the station to be mobile, but the station was stolen backward in time and thus lost. Babylon 5 is immobile because it uses the single spin design, the reason they moved to this design was for budgetary reasons, given that the first 3 stations were lost during or shortly after construction.
As stated above, the station was opened in the year 2258 to be an embassy/League of Nations or as it is known League of Non-Aligned Worlds. The station houses the ambassadors as well as acting as a small city in space. This means greatly accelerated trading agreements may be formed by the member states as the station acts as a cargo port as well. The people living on the station are meant to get used to the idea of living with people of other species, acclimating them and creating relationships. In other words, it was meant to be a hub of personal networking that would strengthen ties between the various species that went there. The EA embarked on the project because of the circumstances that lead to the devastating Minbari War. The Minbari were first approached by a hothead commander, the Minbari ship contained Grey Council and in an error of understanding the EA commander fired on the ship, killing the holy leader of the Minbari. The Minbari attacked viciously and brought Earth and the human species to the brink of eradication. To prevent such circumstances from befalling them or others again, they created the station to bring large numbers of species together to speak face to face, because battlecruisers make bad first contact mediation platforms.
In the promotion of peace it initially failed, in the year 2260 it succeeded from Earth's ever more tyrranical government, the Narn and Centauri fell back into war and the Shadow War was quickly coming upon everyone. During the Shadow War and the Earth Alliance Civil War the station acted as a staging ground for the League to act as an entity in protecting itself. The people involved were able to win both wars and afterward formed the InterStellar Alliance. The ISA succeeded the League and was able to build the peace for which Babylon 5 laid the foundation.