A giant North Korean flag flutters from a 528-foot pole near the border with South Korea. Tunnels built by North Korea's military are believed to extend across the border.
Ahn Young-joon/AP
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North Korea is known for its extensive military tunneling. Along with training thousands more troops, officials say the Pentagon is buying specialized gear such as night vision goggles.
A giant North Korean flag flutters from a 528-foot pole near the border with South Korea. Tunnels built by North Korea's military are believed to extend across the border.
Ahn Young-joon/AP
hide caption
