As NATO gets ready for its biggest military exercise in years, things are heating up closer to Russia

NATO forces are converging on Norway for Trident Juncture, which will be the alliance's largest military exercise in nearly two decades.

But military activity has been increasing on the other side of the Baltic Sea and in Kaliningrad — areas that have long been flash points for Russia and NATO.

Moscow assumed control of Kaliningrad after World War II and retained it after the breakup of the Soviet Union.

Now an 86-square-mile exclave, Kaliningrad is home to about a million people who are separated from the rest of Russia by Lithuania, Poland, and Belarus. But that location makes it strategically valuable.

It has Russia's only Baltic Sea port that is ice-free year-round. In addition to several air bases, it is also home to Russia's 11th Army Corps. It also looks over one side of the Suwalki Gap, which NATO worries could be blocked during a conflict, cutting the Baltics off from the rest of Europe.

Russia appears to be upgrading its military facilities there.

Moscow has in the past deployed Iskander short-range, nuclear-capable missiles there temporarily, but in February, a Russian lawmaker confirmed that the Iskander, which has a maximum range of about 310 miles, had been moved there permanently in response to NATO's buildup in Eastern Europe.

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