Built on the Atlantic, this Moroccan landmark features a roof that opens to stars.

Design · Published 3 October 2026 Swipe more like this →

In short: The Hassan II Mosque in Casablanca is a feat of modern engineering and traditional artistry. Perched partially over the ocean, it boasts the world's second-tallest minaret and a retractable roof that transforms the prayer hall into an open-air sanctuary. It is a monumental synthesis of ancient craft and high-tech resilience.

Commissioned by King Hassan II and designed by French architect Michel Pinseau, the mosque was intended to be Morocco's most ambitious structure. Construction began in 1986, utilizing 10,000 artisans to create intricate zellij tilework, carved cedar, and sculpted plaster. The project was a national endeavor, with 12 million citizens contributing to its 585 million euro cost. Completed in 1993, the complex stands on a promontory, with the prayer hall partially suspended over the Atlantic Ocean, reflecting the King's vision that God's throne is on the water.

The mosque's construction required groundbreaking technical solutions. To build the 210-metre minaret, contractors developed a high-grade concrete four times stronger than standard mixtures, capable of withstanding severe wind and seismic activity. The prayer hall itself is massive, covering 200 by 100 metres, and features a 1,100-ton retractable roof that can open in five minutes. This allows worshippers to pray under the sky, while the hall's central heating and grand scale provide a space that could accommodate a structure as large as Notre-Dame de Paris.

The site's proximity to the sea, however, presented significant challenges. Ten years after completion, salt water migration caused structural deterioration by rusting the internal steel reinforcements. A major restoration project, initiated in 2005, involved removing 6,000 cubic metres of concrete and replacing it with chloride-resistant stainless steel. This intervention is expected to extend the building's lifespan by a century, ensuring that this blend of traditional Moroccan aesthetics and modern engineering remains a landmark for generations to come.

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