Bulgaria was once part of the ancient kingdom of Thrace, and archaeologists there are unearthing many artefacts of great age and importance every year.

However, there is a darker side to the the country's buried wealth, with the rise of organised treasure hunters.

The groups are stealing hundreds of antiquities worth millions of dollars and robbing Bulgarians of an irreplaceable and priceless heritage.

Bulgaria's Illegal Trafficking Squad have recovered hundreds of valuable and irreplaceable antiquities, dating back thousands of years, but thier successes are rare. Stephen Cole reports.