Family lived alone in Siberia for 40 years
A family lived by themselves in the wilderness of Siberia for 40 years — they were completely unaware of the events of the outside world, including World War II. A group of geologists stumbled across them in 1978. The family had originally fled to the wilderness to escape religious persecution. You can read the details on the Smithsonian web site:
For 40 Years, This Russian Family Was Cut Off From All Human Contact, Unaware of World War II