More than five years on, and the so-called Havana Syndrome is back with us.
Four American diplomats have fallen sick this week with suspected cases of the Syndrome in Paris and Geneva.
U.S. Secretary of State Antony Blinken says the federal government is working to identify the illness and who or what might be behind it.
The mystery condition has affected about 200 diplomats and their family members since 2016. Symptoms include migraines, nausea, memory lapses and dizziness
On Inside Story, an in-depth discussion on the causes of this syndrome.