But it's a reminder that the 'known unknowns' in the Spanish case are mainly local.

BBC: Eurozone crisis: what have we learned?

Some of these novel branches were, nevertheless, similar enough to known branches to be accounted for as known unknowns.

ECONOMIST: A new domain of life

These are just some of the many known unknowns, admits Tsuga, who will keynote at the Consumer Electronics Show in January.

FORBES: Panasonic's Next Product: A Small Green Town

As Donald Rumsfeld might have put it, they have left a world of known unknowns for a twilight landscape of unknown unknowns.

ECONOMIST: Financial markets

These "known unknowns" he dubbed "grey swans", in a reference to Nicholas Nassim Taleb's book "The Black Swan", about the nature of unpredictability.

BBC: WPP Martin Sorrell says tax 'a question of judgement'

With so many "known unknowns" haunting the markets in these flighty months of summer, Europe's leaders just have to pray that it is enough, for now.

BBC: One step back from the abyss

Just what proportion of trials are kept under wraps is unclear - one of Donald Rumsfeld's known unknowns - but a 2010 study from the National Institute of Health Research suggests that half are never published, and those with positive results twice as likely to get into print.

BBC: Trust of medical volunteers 'betrayed'

What most people overlooked was that despite seeming like a known solution, the geographic, economic, and cultural distance introduced a significant number of unknowns into the equation.

FORBES: Why Many Social Problems are Entrepreneurial Problems