The city of Greater Sudbury, once a symbol of environmental degradation due to extensive mining activities, has transformed into a modern green city distinguished for its sustainable practices and fertile surroundings. This article explores the remarkable ecological recovery achieved over three decades, beginning in the 1960s, after more than 60 years of environmental devastation caused by sulfur emissions from nickel and copper extraction. These emissions led to widespread soil acidification, severe erosion, and barren landscapes that prevented vegetation from thriving. The recovery was made possible through a collaborative effort involving municipal, provincial, and federal governments, researchers from Laurentian University, and the region's two largest mining companies. This study examines the policies, scientific innovations, and community initiatives that collectively facilitated Sudbury’s transformation into an environmentally responsible city. It highlights how strategic reforestation, soil remediation, and sustainable industry practices revitalized the local ecosystem, offering a model for urban environmental restoration worldwide.