In a globalized world, even local stories can quickly become international. The food we eat, the medicine we take, the clothes we wear and the vehicles we drive -- are all coming from other countries. Following these products' supply chains -- the networks between companies and their suppliers --is a rich field for reporters. Investigations have revealed forced labor, environmental crimes, corruption and human rights abuses. Here are three experts in tracking the use of forced labor, endangered species, and hidden shipping routes.