I believe this is an albumen print, it is printed on thin paper with a shiny finish. It was found among a sheath of photos which all date from an ancestor's Grand Tour of Europe in the 1880s and is most likely from c. 1884.
The Drachenfels (“Dragon's Rock”) is a hill 1,053 feet (321 metres) high, overlooking the Rhine River in Germany, and crowned by a ruined castle built in the 12th century by the archbishop of Cologne that was destroyed by the French in the 17th century.
On the back in period pencil is written "Drachenfels".
THANKS FOR LOOKING!