The Migrant Hawker (Aeshna mixta) occurs in North Africa, southern and central Europe to the Baltic region. It is in the family Aeshnidae and is very similar in appearance to the Southern Migrant Hawker (Aeshna affinis).
Aeshna affinis lacks the T-shaped mark which is found on the top of the second abdomen segment in Aeshna mixta (clearly visible on the photo).

Coto Doñana National Park, Spain, 24 May 2015