Humans have grown plants atop structures since the ziggurats of ancient Mesopotamia (4th millennium BC–600 BC) had plantings of trees and shrubs on aboveground terraces. An example in Roman times was the Villa of the Mysteries in Pompeii, which had an elevated terrace where plants were grown.
Any garden on the roof of a building. They can provide food, temperature control, hydrological benefits, architectural enhancement, habitats for wildlife, and recreational opportunities