The Roma Gym on Calle Orizaba, in the Colonia Roma between Calles Álvaro Obregón and Chihuahua, has picture windows that face the street. For years, the early-evening aerobics classes have attracted an audience of mirones – voyeuristic onlookers. For those who are merely watching, or those who want to replace the lost calories after exercising, the gym is located a few doors down from La Bella Italia, Mexico City’s best ice-cream parlor.