Setting Up Space Cities on the Moon and Mars

Space cities are ideas which need a lot of funding and investment. Colonies on the moon and mars would require large supplies of oxygen and water to sustain people living there. The moon lacks a strong atmosphere and hence it would difficult to think of setting up serious colonies. Though, greenhouses might be a viable option.
Mars is a predominantly red planet due to heavy oxidation of its soil and land and hence mining and industry might be a possible option. Setting up greeenhouses is also a possible option.