Adult Peregrine Falcons have a dark grey-and-white plumage.  
Their chest and throat are white and the belly is white with horizontal dark grey stripes.
Juveniles Peregrine Falcons have a dark brown head and their belly is somewhat brownish with heavy vertical (instead of horizontal) dark brown stripes.
Juvenile remain brown-and-cream colored until they are one year old.

It seems that 19 subspecies of the Peregrine Falcon (Falco peregrinus) have been described.
The one occuring in West, Central and East Europe is Falco peregrinus peregrinus having a white underside with dark grey banding.
In South Europe, it is the subspecies Falco peregrinus brookei which usually shows a rusty underside (clearly visible on the photos).

The Peregrine Falcon is best known for its diving speed during flight which can reach more than 320 km per hour, making it not only the world’s fastest bird but also the world’s fastest animal.

Grotta delle Tre Porte, Santa Maria di Leuca area, Lecce, Puglia, 7 October 2024