It's a family festival, they said. It's for kids who like ships and boats and all things maritime. It's a time for all of Rotterdam to come out, join together and celebrate their history as a port city. That's how they sell Wereldhavendagen - or World Port Days Festival - to you. It's all about family, and fun and celebrating the city's legacy of being one of the most important ports in the world. And it is. It's all of these things and more with a spectacular fireworks...