Keralam is a relatively new museum that opened in the complex near the Napier Museum, focusing on the history and cultural heritage of Kerala from prehistoric times to the modern era. The galleries are well designed and use a mix of artefacts, reconstructions, and multimedia presentations to tell the story of the region's ancient trade links, the spice economy, the various kingdoms that ruled here, and the social reform movements of the 19th and 20th centuries.
For visitors unfamiliar with Kerala history, this is an excellent introduction — more accessible than the Napier Museum's art collection, and with better explanatory text. The sections on the Portuguese and Dutch colonial periods, and on the unique social structure of the Travancore state, are particularly informative. Allow two hours.