New threat

The border between North and South Korea remains heavily guarded 50 years after the bitter Korean War ended on July 27, 1953 with nearly 3 million dead.

The two Koreas are technically still at war having never signed a peace treaty, but have managed to maintain regional stability.

However, North Korea's decision to reactivate its nuclear program has sparked growing international concern and is threatening that stability.

Although tensions show little sign of abating, diplomatic efforts continue to strive for a peaceful end to the nuclear crisis.