Is sinking old ships to make an artificial reef for tourists environmentally friendly? If not, what is to be done with a huge flotilla of rusting, useless commercial and military vessels moored in ports around the world? We delve into this issue with underwater footage filmed off the Spanish coast and in the USA in the Gulf of Mexico where we film one of these sunken ships which has become big business. After 30 years of active service, the Spanish frigate “Baleares” has been decommissioned. Built in the 1970s, many of the materials it is made from are now known to be toxic: PCBs, heavy metals, asbestos, etc. The town of Calvià, on the island of Majorca wants the vessel so they can clean it up and sink it to make an artificial diving reef. Though the Spanish Navy likes the idea, the Environmental Ministry has denied authorization, claiming that no clean-up process can rid the ship entirely of hazardous substances.