The relationship between the city and the natural environment has actually been circular, with cities having massive effects on the natural environment, while the natural environment, in turn, has profoundly shaped urban configurations. Urban history is filled with stories about how city dwellers contended with the forces of nature that threatened their lives. Nature not only caused many of the annoyances of daily urban life, such as bad weather and pests, but it also gave rise to natural disasters and catastrophes such as floods, fires, and earthquakes. In order to protect themselves and their settlements against the forces of nature, cities built many defences including flood walls and dams, earthquake-resistant buildings, and storage places for food and water. At times, such protective steps sheltered urbanites against the worst natural furies, but often their own actions – such as building under the shadow of volcanoes, or in earthquake-prone zones – exposed them to danger from natural hazards.