Les Halles was the traditional central market of Paris. In 1183, King Philippe II Auguste enlarged the marketplace in Paris and built a shelter for the merchants, who came from all over to sell their wares. In the 1850s, the massive glass and iron buildings that Les Halles became known for were constructed. Les Halles was known as the "stomach of Paris".
Émile Zola's 1873 novel Le Ventre de Paris (The Belly of Paris) revolves around Les Halles.
Unable to compete in the new market economy and in need of massive repairs, the colorful ambience once associated with the bustling area of merchant stalls disappeared in 1971, when Les Halles was dismantled, and replaced with an underground modern shopping precinct, the Forum des Halles. It is notable in that the open air center area is below street level, like a pit, and contains sculpture, fountains, and mosaics, as well as museums including the Musée Grévin - Forum des Halles (a wax museum).
Beneath this lies the underground station Châtelet-Les-Halles, central hub of Paris's express urban rail system, the RER.
from wikipedia.org

