Since its founding in the mid 19th century, Portland's leaders have recognized and emphasized the value of public parks as places of recreation, exercise, and spiritual restoration. At that time, cites were struggling with the effects of rapidly expanding populations due to industrialization. Overcrowding, noise, sewage, and air pollution were often endemic and threatened the health and well being of residents. Many began to advocate for parkland and green space as a place of refuge and relief from the industrial city.