Where on Earth is Osama bin Laden?
America's failure to capture Osama bin Laden and the lack of sightings of the world's most wanted man have fostered many theories, some bizarre, about his whereabouts.
The CIA believe the al Qaeda founder is hiding in the rugged tribal regions of north-west Pakistan, though American defence officials concede there has been no hard intelligence on his location in years.
Officials have named Chitral, Kurram and Waziristan as potential havens, where he would be protected by locals and perhaps elements of Pakistan's intelligence services.
In February 2009 a Californian geography professor used mathematical techniques for hunting endangered species to pinpoint three houses in Parachinar, 12 miles from the Afghan border.
Thomas Gillespie narrowed his search by factoring in bin Laden's need for security, electricity, high ceilings to accommodate his 6ft 4in frame and spare rooms for his bodyguards.
Far from living as a fugitive in the mountains, the terrorist mastermind was living in luxury in Tehran and spending his time falconing a documentary alleged last year.
Mahmoud Ahmadinejad, Iranian president, retorted that bin Laden was in Washington. He said: "Rest assured that he's in Washington. I think there's a high chance he's there."
A Taliban detainee in Pakistan told his interrogators that bin Laden had been seen in the eastern Afghan province of Ghazni as recently as early 2009.
Many believe bin Laden is in fact long dead and his messages are faked.
He has been variously reported as killed during fighting at Tora Bora soon after the American invasion of Afghanistan, or dead from typhoid caught in Pakistan.