In his series “What Coal Left Behind,” photojournalist Matthew Busch looked to Europe — Walbrzych, Poland, specifically — to explore the human impact of harvesting fossil fuels, and the people involved either directly or indirectly in the practice. “I’m interested in a place where a resource that was once used to build up an entire region and created a rich heritage is now mined and sold illegally. Regions of Poland are still productive, but I wanted to see how an area was affected after industry had left.”