When it opens its doors next year, the 1,500-capacity Essalam mosque will serve the port city's rapidly growing Muslim community.
But not everyone in Rotterdam is happy.
Marco Pastors is a city councilor who spearheaded the protests. "We are not especially anti-Muslim," he says.
"[But] you have to earn the right to make very distinctive buildings when you are new in a country. If you look at the integration in Holland, we have a lot of problems fitting Muslims into our society -- getting them to work, [influencing] their opinions about homosexuality, about the difference between men and women in a marriage -- and we are working on that very hard. We think they have to adjust [to Dutch society], and as long as they are not adjusted you have to take care that everything you do with Muslim organizations is in the [context] of adjusting, in the [context] of listening to each other. If you listen to a big part of the Rotterdam population, [Muslims] have to do that also in the design of the mosque, and that's the subject we wanted to make clear to them," Pastors said.
In the end, the mosque's opponents lost out. Construction began last October -- according to the original design.
Such controversies are not specific to Rotterdam. In other European cities, too, the building of new mosques has encountered fierce resistance.
In Greece, authorities want to build the first mosque in the Athens area in nearly 200 years to open in time for this summer's Olympics. But the mayor of Peania says the town doesn't want the mosque.
In Slovenia, plans to build the country's first mosque prompted thousands of opponents to sign a petition earlier this year. That was enough to force the Ljubljana city council to call a referendum, though the mayor last month said she would block the vote.
Liz Fekete researches racism in Europe at Britain's Institute of Race Relations. She says, "Two years ago, I was not monitoring this sense of opposition to mosques. I would say I only really started to be aware of it in the last year. And for me in the last few months, every single week I'm coming across new cases -- in Spain, Italy, and France."
Typically, opponents say they worry about the erosion of their own culture. Some, like in Slovenia, say they fear the mosques may be a breeding ground for terrorists.
But for Europe's growing Muslim population, rows like these are yet another front in their battle for acceptance.
Yassin Hartog is a spokesman for the Netherlands-based Muslim group Islam and Citizenship. He says people there became more critical of Islam following the rise several years ago of Pim Fortuyn, the anti-immigrant politician who was later murdered.
"[Objections to the mosque] demonstrate a basic fear among, especially, right-wing opposition that is en vogue at the moment in Holland. They voice the fears of many people in the general public [about] the fact that we have so many migrants living in Holland populating over half of our four major cities -- that this will bring about a change of the public sphere in which the original Dutch population doesn't recognize itself. It's basically the people who object to this change of culture and climate who object to these mosques. But basically, of course, it's also a way of obstructing Muslims in the way they can live up to their faith," Hartog said.
Fekete gives one more reason for the rise -- the war on terror, she says, has stigmatized Muslims as potential terrorists in the minds of many Europeans.
She links the opposition to mosques with other attempts in Europe to curb the influence of Islam, like France's ban on Muslim headscarves in public schools.
"It's the idea now that Muslim communities have to engage in some sort of integration contract with the host society. There is this idea, and it has been explicitly said in France during the whole debate about the hijab, that we want a European version of Islam, and that Islam must adapt to Europe, not Europe adapt to Islam," Fekete said.
In Rotterdam, Pastors would agree with that. And though he has lost the battle over the Essalam mosque, he says he's ready to use the experience to fight future mosque plans.
Essalam, he says, will be the last mosque in his part of Europe built in the traditional way.