Fifty percent of the world’s population live in cities, and there are approximately 557,000 cities worldwide. Many needs, challenges and problems are common, and so are solutions, even if many cities have different conditions. Citymart is a service seeking to help cities to both define their problems and find the right solution. Citymart is the matchmaker that finds the right solutions and shares them among cities in need to overcome their own local challenges. Sascha Haselmayer was one of the speakers at the seminar Tipping Point, and we met him in a conversation about cities, sustainability, challenges and innovation.