This image was acquired from
wikimedia. 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:
Coal formation Manitou Grand Caverns NYPL bGF ZF. en Coal formation Manitou Grand Caverns nypl org Scan by NYPL Coal formation Manitou Grand Caverns Hook The Miriam and Ira Wallach Division of Art Prints and Photographs Photography Collection eaaecfcdabc GFZF Robert Dennis collection of stereoscopic views decadeeaa NYPGF repo