 Good morning. I'm Sasha Pfeiffer. Some cities in Europe are discouraging tourists from visiting this summer, but Copenhagen is welcoming them with open arms and one condition. Denmark's capital is starting a new campaign this month, encouraging tourists to go green while they visit. The Copenhagen Pay Program wants visitors to pick up trash and avoid driving cars. In exchange, the city will pass on credits for free food, guided museum tours, even kayak rentals. It's Morning Edition.