Mars is to open its first European M&M's World store in a 35,000 sq ft site in London's Leicester Square. The store, in a retail unit at the base of the the W Hotel on the site of the former Swiss Centre, is expected to open next summer. The confectioner already has three M&M's Worlds, in Orlando, Las Vegas and New York. They stock merchandise, sweets, souvenirs and provide a range of M&M's-related entertainment.