Complex sentence: On 2 March 2014, early in the 2014 Crimean Crisis, a checkpoint was set up in Armyansk by Russian Naval Infantry units without cockades or rank insignia, checking cars driving in and out of the Crimea region.
Split into simpler sentences: On 2 March 2014, early in the 2014 Crimean Crisis, a checkpoint was set up in Armyansk by Russian Naval Infantry units without cockades or rank insignia. They check cars driving in and out of the Crimea region.