Polish filmmaker Bartosz Konopka recounts the history of the Berlin Wall from the perspective of rabbits trapped in the no-man's land created by the structure. Freed from hunting pressure, they multiplied and prospered. After all, no one was shooting at them. Such structures, known to biologists as "exclosures," often belie their brutal genesis with an unintended beneficial impact on wildlife. After all, they exclude the most destructive of predators: people. The DMZ between North and South Korea is said to be teeming with otherwise endangered wild animals. Until the cleanup began last summer, the fenced-off Sydney Tar Ponds was...