Google Image search was no help. I came across it on this page: http://www.europeana1914-1918.eu/el/contributions/1186#prettyPhoto
It's an Italian 305mm gun in a de Stefano carriage. The carriage was designed to mobilise Naval guns for land use.
There were a number of possible guns used with this carriage including the 305mm L/40 M1901 Armstrong and 305mm L/46
M1909 Armstrong-Vickers.
Regards,
Charlie
Wow, that was quick. Thanks. I thought it was German.