According to a South Korean NGO, it has identified 318 sites in North Korea that have been used by the government to carry out public executions.
The Transitional Justice Working Group interviewed 610 North Korean defectors over four years for its report.
It documented decades of killings, for offences ranging from stealing a cow to watching South Korean TV.
Public executions took place near rivers, fields, markets, schools, and sports grounds, the rights group said.
Crowds of 1,000 or more would gather to watch these executions, the NGO said in its report, "Mapping the fate of the dead", released on Tuesday.