Hassan II Mosque

In 1980, Hassan II announced he wanted a mosque on the Atlantic. Not beside it — on it. The reasoning was theological: the Quran says God's throne rests upon water. The engineers said it was impossible. Hassan II hired the French architect Michel Pinseau, a man who had never designed a mosque.

Pinseau spent six years on it. The foundation required 26,000 tonnes of steel driven into the ocean floor. The retractable roof — 3,400 square metres of cedarwood — opens in five minutes, which means the prayer hall can become open-air at the push of a button. Think of the retractable roof at Wimbledon's Centre Court, then add a 210-metre minaret.

That minaret is the tallest religious structure in Africa. At night, a laser beam shoots from its summit toward Mecca, visible 30 kilometres out to sea. The construction employed 10,000 workers in shifts around the clock for seven years. It cost an estimated $800 million, financed partly by public donation — some voluntary, some less so.

The mosque opened in 1993. Hassan II attended the first prayer but died six years later, in 1999. He is not buried here. His mausoleum is in Rabat.

This is one of the only functioning mosques in Morocco open to non-Muslims. That fact alone makes it essential. Guided tours run in multiple languages and last about an hour. They cover the prayer hall, the ablution rooms, and the hammam level.

The tours are managed, not wandering — you go with a group and a guide, which means you cannot linger. Photography is allowed inside, which is rare for Moroccan mosques. The exterior esplanade is open anytime and is where Casablancais walk in the evenings. The best light hits the minaret at sunset, when the white granite goes amber.

Friday is prayer day. Tours do not run during prayer times. Dress modestly — covered shoulders and knees, shoes removed inside. The marble floors are cold, even in summer.