Jerry Slocum spent 50 years assembling the world's largest collection of mechanical puzzles — around 30,000 objects, from ancient Chinese ring puzzles to contemporary Japanese burr puzzles, from the original Rubik's Cube prototypes to 19th-century puzzle boxes. In 2006 he donated the entire collection to the Lilly Library at Indiana University, where it is now available to researchers and shown in rotating exhibitions.
The collection is not permanently on public display, but the Lilly Library incorporates puzzle items into its regular exhibitions and the collection can be accessed by appointment. What makes it remarkable is its scope: this is not a toy collection but a serious historical archive of human problem-solving ingenuity, with examples from every culture that has produced puzzles and every century from which examples have survived. If you are visiting the Lilly Library and mention an interest in the puzzle collection, staff will often show you examples.