Venus is the second planet from the sun, after Mercury and before Earth. It has an extremely thick atmosphere, and temperatures at the surface are hot enough to melt lead. However, at an altitude of approximately 50 kilometers, the pressure and atmospheric temperature are Earth-like. It has been suggested that floating settlements, using breathable air as a lifting gas, could be used to colonize Venus. From the chemical break down of carbon dioxide and sulfuric acid and from free nitrogen in Venus' atmosphere carbon, oxygen, nitrogen, sulfur and hydrogen are all available on Venus. This could provide the local source for plastic and carbon fiber building materials, breathable air and water. Unfortunately, due to a lack of mining opportunities, Venus settlements cannot be built completely from local materials. A colony on Venus would require a thriving colony on Mars, Luna or more probably both as a prerequisite because the large initial investment of material to initiate a colony in Venus' atmosphere could not be reasonably be lifted out of Earth's gravity well. A Venus colony should provide continuing trade opportunities for a Mars colony. There could be a three way interplanetary trade in which Venus provides carbon and nitrogen to Luna, Luna provides solar cells and metals to Mars and Venus, and Mars provides hydrogen to Luna and Venus. Mars, Venus and Luna would together provide various materials to orbiting habitats and factories in cis lunar space. Trade and economic development will be essential for all human colonization beyond Earth.