Hengqin in China is home to Ocean Kingdom, a theme park with one of the largest aquariums in the world. A mammoth structure of glass, steel and concrete, it was built with the collaboration of experts from around the world and 20,000 Chinese workers, at the estimated cost of 5 billion dollars. This unique indoor ocean holds 50 million litres of water and 5000 species of marine creatures. Witness the efforts, technology and innovations that resulted in the creation of this architectural marvel that is now the delight of millions of visitors.