Action of 21 May 1918
{'<entity_0>': 'Action of 21 May 1918', '<entity_1>': 'Atlantic Ocean', '<entity_2>': 'World War I', '<entity_3>': '21 May 1918', '<entity_4>': 'Spain'}
[['Action of 21 May 1918', 'part of', 'World War I'], ['Action of 21 May 1918', 'point in time', '21 May 1918'], ['Action of 21 May 1918', 'start time', '21 May 1918'], ['Action of 21 May 1918', 'end time', '21 May 1918'], ['Action of 21 May 1918', 'location', 'Atlantic Ocean'], ['Action of 21 May 1918', 'location', 'Spain']]
The <entity_0> was a naval engagement of <entity_2> fought between an American armed yacht and a German submarine in the <entity_1> off <entity_4>. On 24 <entity_3>, the U-boat arrived at Santander, <entity_4> after a dangerous three-day voyage in a severely damaged condition.
['conflict']