Founded by a well-off philanthropist looking to preserve the history of life before the Industrial Revolution, the Mercer Museum is a fascinating look at a time gone by. Housed in a poured concrete castle, this massive collection tops nearly 30,000 items — everything from wagons and threshing machines to wooden buckets and hand tools — with the largest items housed in the central atrium, and others spread throughout the various niches, rooms, and coves. Notice the other castle on the grounds? Not to worry — it's Mercer's former home, and is also open to the public.