After the outbreak of the Spanish Civil War in July 1936, most of the major naval powers, along with a few lesser states, sent and kept warships in Spanish waters.
Frank, Willard C. Jr.
"Misperception and Incidents at Sea: The Deutschland and Leipzig Crises, 1937,"
Naval War College Review: Vol. 43
, Article 4.
Available at: http://digital-commons.usnwc.edu/nwc-review/vol43/iss2/4