The former KGB building on Brivibas and Stabu is one of Riga's most sobering historic sites. Its ornate exterior gives little warning of the prison cells and interrogation rooms inside, now presented as a branch of the Museum of the Occupation of Latvia.
The general exhibition explains Soviet security work in Latvia, but the guided cellar tour is the reason to come. It is heavy material, and all the better for being shown in the actual building where it happened.