Complex sentence: The Busch-Reisinger was located in Adolphus Busch Hall from 1921-1991 and the hall continues to house the Busch-Reisinger's founding collection of medieval plaster casts, as well as an exhibition on the history of the the museum.
Split into simpler sentences: The Busch-Reisinger was located in Adolphus Busch Hall from 1921-1991. The hall continues to house the Busch-Reisinger's founding collection of medieval plaster casts and an exhibition on the history of the the museum.