I received this wonderful card in the Slavic countries & Rest of the world RR. Borovnica is a town in Slovenia. It's name means "blueberry".
Fortunately, the sender was so kind to translate the information about this card into English :) I understand Slovene, but not good enough to translate it into English myself.
Borovnica viaduct: 510 m long and almost 40 m high railroad viaduct was built in years 1850-1856 as a part of railroad Vienna-Trieste. During World War 2 was partially demolished by retreaving Jugoslav army, later was bombed by ally aircrafts. After was was finally demolished and left only one column which remembers about that masterpiece.