The Odessa Catacombs.

1,600 miles long. It is one of the world's largest urban labyrinths.The Catacombs are on three levels and reach a depth of 60 metres (200 ft) below sea level

These mines were abandoned and later used, and widened, by local smugglers, creating a labyrinth of tunnels beneath Odessa.

Stories of smugglers are part of urban legends about treasures hidden underground. What kind of treasure? Black Sea ports+catacombs+trafficking?

https://en.wikipedia.org/wiki/Odessa_Catacombs

South America became a very important player in Ukrainian drug trafficking in the past 20 yrs.

The Growing Importance of Ukraine as a Transit Country for Heroin

https://www.ncjrs.gov/pdffiles1/nij/grants/196664.pdf

Ukraine: At The Center Of The East-West Drug Trade

https://www.rferl.org/a/1077895.html

With a green light from top officials, Ukraine is turning into one of the biggest drug transit countries on the way to the EU

https://ukrainianweek.com/Society/88757

2012 book, "Ukrainian Drug Trafficking"-Latin American and Afghan drug cartels are trying to set up a transit point in Ukraine to move cocaine and heroin to Western Europe.

They may get help from corrupted local authorities. Almost 70 million drug doses are consumed in Ukraine each year. Also, tons of drugs are produced in Ukraine itself.

The Odessa Catacombs.

1,600 miles long. It is one of the world's largest urban labyrinths.The Catacombs are on three levels and reach a depth of 60 metres (200 ft) below sea level

These mines were abandoned and later used, and widened, by local smugglers, creating a labyrinth of tunnels beneath Odessa.

Stories of smugglers are part of urban legends about treasures hidden underground. What kind of treasure? Black Sea ports+catacombs+trafficking?

https://en.wikipedia.org/wiki/Odessa_Catacombs

South America became a very important player in Ukrainian drug trafficking in the past 20 yrs.

The Growing Importance of Ukraine as a Transit Country for Heroin

https://www.ncjrs.gov/pdffiles1/nij/grants/196664.pdf

Ukraine: At The Center Of The East-West Drug Trade

https://www.rferl.org/a/1077895.html

With a green light from top officials, Ukraine is turning into one of the biggest drug transit countries on the way to the EU

https://ukrainianweek.com/Society/88757

2012 book, "Ukrainian Drug Trafficking"-Latin American and Afghan drug cartels are trying to set up a transit point in Ukraine to move cocaine and heroin to Western Europe.

They may get help from corrupted local authorities. Almost 70 million drug doses are consumed in Ukraine each year. Also, tons of drugs are produced in Ukraine itself.