Skako
this city-covered planet was the homeworld of the Skakoan race. The atmosphere of Skako was filled with methane and other unusual chemical compounds, many of which were incredibly heavy. This meant that the atmospheric pressure on Skako was extremely high, making it unlivable to many other species. The Skakoans, however, evolved over time to survive there. This meant that nearly all Skakoans remained on Skako, since the equipment needed to maintain the unusual atmospheric pressures of Skako was prohibitively expensive.