The Valyrian Freehold enslaving the people of Old Ghis
Slavery is the system under which people are treated as property to be bought and sold, and forced to work. Though slavery is outlawed in Westeros, it is widespread and prosperous in Essos, especially in the eponymously named Slaver's Bay: however this status quo has been called into question as war ravages the region, with Daenerys Targaryen proclaiming she will exterminate the practice.