Gardiner's manufacturing and transportation advantages during the first half of the 20th century created one of the strongest local economies in the state. The city seal, adopted in 1849 when Gardiner became a city, flawlessly depicts the characteristics that shaped the community. Featured prominently on the seal is a river with falls to power manufacturing. A vessel represents transportation and trade, while an idealized city in the background reveals prosperous factories and commercial buildings. At the top is a lofty church tower, representative of the many churches in the city. Gardiner features many never-before-published postcards from the collections of the Maine Historic Preservation Commission.