The Great Spotted Woodpecker is the most common and widespread woodpeckers in Europe.
It has black and white plumage, a prominent oval-shaped white patch on each wing and a red underbelly (trousers). 
Males have a red patch on the rear of the head which females don't have.
Juveniles can be identified by their red crown which they loose after their first mould (August - September).

1st & 2nd photo: A male. Stadtgarten, Überlingen, Baden-Württemberg, Germany, 12 August 2020
3rd photo: A male. Eifel National Park, near Camping Schafbachmühle, North-Rhine Westphalia, Germany, 5 May 2022
4th photo: A female. Strandbad Sehestedt, Wilhelmshaven area, Lower Saxony, Germany, 16 August 2023