In the 1970s, the US dumped up to 2 million tyres off Florida's coast to help marine life. More than 50 years later, the cleanup is still underway

• Millions of old vehicle tyres were placed offshore near Broward County for artificial reefs.
• Shifting currents and storms scattered these tyres, damaging existing coral reefs.
• Government agencies are now undertaking a massive, multi-year cleanup operation.