While Muslims represent about 4% of Spaniards, they are 8% in Catalonia. So it makes sense that the first attacks in Spain take place in Catalonia.
In downtown Turku – where most of Finland's Muslims live (so it makes sense, too; note that only 1% of Finns are Muslims) – one person died and six were injured after a person screamed Allahu akbar. In Barcelona, a white van rented by a man of Moroccan ancestry has driven on the sidewalk of La Rambla, a popular tourists' boulevard, and killed 14 people. A few hours later, five Muslims – some of them had fake explosive belts – had to be killed in Cambrills after their Audi A3 tried to overrun pedestrians as well.
I guess that many of you have been to Barcelona – I have been there but it's years ago. La Rambla is an impressive boulevard. You can virtually borrow another white van, Google's van, and drive through these 550 meters just like the terrorists. You should stop at this Joan Miró mosaic. How many people do you estimate that you would murder if you tried to maximize the number?
Some of the weapons that these terrorists are using have become so popular that one could save many lives by restricting the Muslims' access to certain dangerous tools.
I think that in European countries, Muslims shouldn't be allowed to drive vans and big cars in general. As a compensation, they could have free public transportation in every city or something like that.
Also, they shouldn't be allowed to carry guns and knives in the public. This wouldn't be such a harsh restriction. During the Ben Ali years, the Tunisian men couldn't have owned knives, either.
Obviously, some readers would ask me how it would be decided who is a Muslim. Well, in your IDs or passports, you would have a written comment or label that determines whether you are a Muslim. If your label said "non-Muslim", it would be illegal for you to attend prayers in mosques and similar events, to increase the probability that Muslims wouldn't try to present themselves as non-Muslims.
Muslim men should also be prohibited from wearing outfits that allow them to hide explosive belts and big enough guns and similar things. Accidental checks by policemen should become standard and whenever they would turn out to be OK, the suspicious people could be paid €1 by the cop as a compensation.