An enormous fifty-year-old ocean liner, the SS United States, is set to be sunk and become the world’s biggest artificial reef, off the coast of Florida in the US. The area already has over 500 artificial reefs. These are manmade structures that may mimic some of the characteristics of a natural reef. The people behind it say it’ll improve biodiversity, local tourism and fishing.

And it’s not just old ships; people have sunk oil rigs and subway carriages. They don’t always have a positive effect; in the 1970s two million tyres were dropped into the ocean to try to create an artificial reef (also off the coast of Florida), but they released lots of toxins.

Climate and science reporter Georgina Rannard explains how ships like this get turned into artificial reefs and whether old ships are good for marine life. We talk about other kinds of artificial reefs and ask what benefits they can have for our oceans.

Archive courtesy of British Pathé and CBS News.

Instagram: @bbcwhatintheworld