Gibraltar

Gibraltar Chief Minister Fabian Picardo said the vessel was released "in light of the assurances we have received" from Iran.

Anger, frustration, even an unsubtle suggestion of war — there's been some heated talk lately between the U.K. and Spain about a single rock. Here's a primer on what all the fuss is about.

Gibraltar had a reputation as a tax haven and hosts Mossack & Fonseca, the law firm at the center of the Panama Papers. But Gibraltar has made reforms and insists it's a proper place for business.