Nearly two decades after the bombing of a Jewish community center in Buenos Aires, Latin America’s deadliest terrorist atrocity is roiling Argentina once again. Prosecutors long ago blamed Iran, but Tehran denies any involvement. Now, a new effort by Argentina President Cristina Fernandez de Kirchner to get to the bottom of the mass murder mystery has triggered widespread outrage.

In recent months, the world has imposed unprecedented sanctions on Iran, and its economy has been battered as a result. In response, Iran has threatened to disrupt tanker traffic in the Straits of Hormuz, a strategic chokepoint through which about one-fifth of the world’s oil flows. Here's what you need to know.