One of These Things is Not Like the Others

From a glance at Yahoo News's Top Stories from AP section this afternoon, here's this week's discussion question:

Which one of these is not like the others?

* Iran Threatens to Block U.N. Inspections
* Forensic Clues Could Explain Mine Disaster
* Alaska Volcano Erupts Third Time in a Week
* Tyco to Split Into 3 Cos. at Cost of $1B
* Angelina Jolie and Brad Pitt Visit Haiti

Please keep the discussion civil and do not wander off into "What? Nothing more about the sobbing Mrs. Alito?" or "This must be a definition of top that I was not previously aware of."

Discuss.