Until this fall, the factory complex of Grand-Hornu, in Belgium's mining region, was more likely to conjure up coal than contemporary art. Now the Musée des Arts Contemporains, known as MAC's, has risen phoenix-like from the ruins of the 19th-century colliery, and installations by artists such as Christian Boltanski can be viewed alongside photographs documenting the factory's history. Once a utopian vision of industry, the complex comprised workers' housing of some 425 modular units (each with its own vegetable garden), a school, library, hospital, and dance hall. Nearly 20 years after the last shaft closed in 1954, a local architect bought the site and opened a historical museum. In 1989, Grand-Hornu was acquired by the province of Hainault, and the idea for MAC's emerged soon after. But it was 11 years before the museum (designed by Pierre Hebbelinck) was built. Of concrete, steel, and wood—and bricks painted coal black—it plays beautifully off the original red and gray structures. 82 Rue Ste.-Louise, Hornu;