In the area between the Black and the Caspian Seas lie countless festering issues, including separatist disaffection in two parts of Georgia, a territorial row between Azerbaijan and Armenia, and the question of a pipeline to carry oil to the Mediterranean via Turkey.

ECONOMIST: Russia’s brutal folly | The

An oil pipeline between the Caspian and Black seas, which avoids Russia, was declared open.

ECONOMIST: Marking time

Dagestan is one of seven small republics within the Russian Federation that together comprise Russia's North Caucasus region, a predominantly Muslim area which itself is wedged between the Caspian and Black Seas.

CNN: Boston bombing suspects: The Dagestan connection