For almost two decades, Estonia was ravaged by the man-made drug fentanyl, a highly addictive opioid that is 50 times stronger than heroin. The drug used to kill one person every three days in the tiny Baltic state. But deaths have now plunged to less than a quarter of what they were, thanks to a police and public health drive which has made Estonia a rare good-news story in the desperate fight against fentanyl. Experts warn, however, that Estonia's success may be difficult to replicate in other opioid crisis hotspots, such as the US where the drug killed 32,000 people last year.