Tito's bunker

This is the story of one of the largest and best-kept secrets of the former Yugoslavia, once a miracle of construction, special, extraordinary and complex for a special purpose — a secret facility called D-0.
Objekt D-0 is also known under the names of ARK (army reserve command) or «Tito's nuclear bunker». D-0 is constructed in strict secrecy, under the heading «The strictest state secret», and the construction lasted for 26 years, from March 1953 by September 1979.
The purpose of the building is, as it can be seen from the name, accommodation and protection of closest political and military leadership of the Socialist Federal Republic of Yugoslavia in the case of an immediate nuclear threat.