Over 2 billion euros to buy Barcelona's bullring La Monumental - that's what's being offered by the Emir of Qatar to turn the now empty venue into a giant mosque, the third largest in the world. It would finally give Catalonia's Muslim community, which makes up 6% of the population, a dignified place of worship. Muslims in Barcelona currently pray in makeshift mosques in converted garages, shops and houses. But the scale and the location of the project are proving controversial.