This image was acquired from
flickr. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
castalia castalia ohio castaliaohio blue hole bluehole the blue hole thebluehole tourist sites touristsites c.t. artcolortone ctartcolortone curteichchicago curteichchicago curteich e.b. ackley ebackley linen postcard postcards divided back dividedback white border whiteborder white border era whiteborderera text Description on front