The Watkins Museum of History at 1047 Massachusetts Street covers Lawrence's history from its founding as an abolitionist settlement in 1854 through the present day. The collection focuses particularly on the Bleeding Kansas period and the Civil War — the sacking of Lawrence in 1856 and Quantrill's Raid in 1863 are both covered in considerable depth, with primary documents, artefacts, and photographs.
The museum occupies a handsome Beaux-Arts bank building from 1891, which gives the visit a double interest — the building itself is one of the finest on Massachusetts Street. Admission is free or by donation. It's small enough to see in an hour and substantive enough to be worth that hour.