If you'd like to see a rat (as in rats), go to one of the city parks on trash day. The cans get emptied 24-48 hours before the trucks pick them up. Go there in the evening and sit maybe 30 meters from the trash heap. Watch carefully. Extra credit: Toss them french fries.

If you're up for a more disturbing experience, go sit on those benches at the south end of Riverside Park--the ones next to the ivy or whatever. Listen for the squeaking. Guess what? Those are rats. Lots and lots of rats, like in Jurassic Park or something.