Human trafficking is the 3rd largest crime industry in the world, and to find slaves you just need to go wherever there are prostitutes in your area.
Yes, even when prostitution is legal, for example Germany is one of the main destinations in Europe.
EDIT: Some useful FAQ from the EU website on the matter are here https://ec.europa.eu/anti-trafficking/citizens-corner/traffi...
> Yeltsin, then 58, "roamed the aisles of Randall's nodding his head in amazement," wrote Asin. He told his fellow Russians in his entourage that if their people, who often must wait in line for most goods, saw the conditions of U.S. supermarkets, "there would be a revolution."[0]
The difference between the first and second world was a objective distinction in prosperity experienced by inhabitants in the different systems.[0] The first world capital allocation was several orders of magnitude more efficient than the Soviet block.
[0] https://www.nhregister.com/neighborhood/bayarea/news/article...
But the expression "third world" arose to mean "neither NATO nor Warsaw pact" and only later started to mean "poor" because most of the countries in this group were. See wikipedia's references[0]. There were poorer countries in the communist block, and richer non-aligned ones.