Strange Geographies is going to Venice! What should I shoot?

So, this is cool. Most of our regular readers are probably familiar with my series of photo essays, Strange Geographies. Well, next week I'm packing my bags for Italy, and will be spending four days and five nights in one of the strangest and most beautiful places on Earth -- Venice. Here's my challenge, and where our readers come into the picture. Three million tourists flock to Venice every year, but if you've read any of my photo essays, you know that tourist traps aren't exactly my cup of tea. I'm looking for the unusual, dark, haunted, underground, flip-side of Venice that isn't on the tourist maps, and I'd love to get lots of suggestions from our readers for spots that would make a good Strange Geographies essay.

Leave your ideas in the comments, and whichever person's topic I end up using will get an 8x10 print from that photo essay and a mental_floss tee-shirt. Can't wait to hear what you guys come up with!