The city of Barcelona became the world capital of sustainability for three days after hosting four international events focused on sustainable development at Fira de Barcelona's Gran Via. Over 32,000 professionals from a hundred countries discovered the latest innovations, trends and technologies, as well as sharing experiences regarding smart cities, energy, the integral water cycle and circular economy through the Smart City Expo World Congress, Circular Economy European Summit (CEES), iWater and the European Utility Week.