Route: Szlak Orlich Gniazd (Poland)

The Trail of the Eagle's Nests (Polish: Szlak Orlich Gniazd) of south-western Poland, is a marked trail along a chain of 25 medieval castles between Częstochowa and Kraków. 

The Trail of the Eagles' Nests was first marked by Kazimierz Sosnowski. Since 1980, much of the area has been designated a protected area known as the Eagle Nests Landscape Park (Polish: Park Krajobrazowy Orlich Gniazd).

Wikipedia: https://en.wikipedia.org/wiki/Trail_of_the_Eagle%27s_Nests

Map: https://mapa-turystyczna.pl/route?q=50.0883730,19.9306800;50.8119380,19.1288440&v=1