This was the ablutions room under the prayer hall, filled with fountains like this one. They were nicer looking than this capture might indicate, but there were so many tour groups going through at the same time, it was hard to get a view of them.
“With a prayer hall that can accommodate 25.000, the Hassan II Mosque is the second-largest religious building in the world, after the mosque in Mecca. The complex covers 9 hectares (978,774 square feet), two-thirds of it being built over the sea. The minaret, the lighthouse of Islam, is 200 m (656 feet) high, and two laser beams, reaching over a distance of 30 km (18.5 miles) shine in the direction of Mecca. The building was designed by Michel Pinseau, 35,000 craftsmen worked on it, and it opened in 1993. … [It] is a monument to Moroccan architectural virtuosity and craftsmanship.” (“Eyewitness Travel, Morocco”)
Lighting in the ablutions room, posted earlier: