If you're in Tokyo, have a strong stomach, and are in the mood to see the world's one and only museum of Parasitology, all you have to do is hop on a subway and head to Meguro. Atlas Obscura explains the organization of the museum. The first floor is the least-gross, given the subject matter, and features parasites that infect animals. The second floor is full of parasites that infect humans. "Photographs show the severely distended testicles of the unfortunate human host of a tropical bug." The museum contains over 45,000 parasite specimens on display, including the world's largest tapeworm (8.8 meters).