Inside former gulag barracks, this excellent exposition (in Russian) takes you through the different stages of the Solovetsky gulag – from punishing 'counter-revoluntionary elements' and providing a slave labour force to build the infamous Belomorsky Canal, to the summary mass executions during the Great Terror of 1937-38.
Bold displays are interspersed with gulag prisoner testimonies and a short black-and-white film at the end merges truth and propaganda – real inmates are the ones not looking at the camera.
A tour by the knowledgeable local archivist (R400) makes the visit particularly worthwhile; book at the tourist office.