The Regional History Museum traces Vitebsk's long history from prehistoric settlements through the medieval Grand Duchy of Lithuania, the Russian Empire period, and the catastrophic years of World War II. The WWII section is the most substantial: Vitebsk was almost completely destroyed during the war, and the museum documents both the occupation and the destruction in considerable detail. It is not easy viewing, but it is important context for understanding why so little pre-war architecture survives.
The museum is housed in a period building near the city centre and covers several floors. Labelling is primarily in Belarusian and Russian, so some patience is required if you do not read either language. The archaeology rooms on the lower floors have some interesting finds from the medieval city.