• The U.S. and South Korea start 10 days of joint naval exercises today, under the shadow of North Korean threats to lash out with missiles aimed near Guam over what it sees as rehearsal for an invasion. Above, the U.S.S. Michigan, a nuclear-powered submarine, will take part.

Meanwhile, North Korea has quietly developed another dangerous capability. With a cyber army of more than 6,000 hackers, it is stealing hundreds of millions of dollars and proving capable of unleashing global havoc.