Here, as a community service for serial killers on vacation, is a list of suggestions for dumping the body in various world cities.
Paris, FranceParis has a terrific disposal spot! First, place the body in a vat and render it down to bones. Now take the bones and visit the Catacombs of Paris. This is an underground ossuary which has been in use for over two centuries. The place is chock-a-block full of human bones; at least tens of thousands of them, many arranged in interesting patterns, but most simply stacked.
Be careful to place your new additions underneath some of the older existing ones.
New York, United StatesJanet Reid, with whom I will be careful to avoid riding the subway, suggests: "You could stuff a body in an unused subway tunnel, cover it in lime, and Bob's your uncle. Your dead uncle, but still."
Sydney, AustraliaFeed 'em to the sharks. This requires a boat - easy to come by in Sydney. It should be straightforward to disguise the body inside a sail bag. Sail out of the harbour onto open ocean, wait for sharks. Feed.
This innovative solution has only ever gone wrong once, but when it did, it was in spectacular fashion. In 1935, a recently captured shark at a public aquarium, while a crowd watched, disgorged a human arm, which proved to belong to an underworld identity who, funnily enough, had been missing for some days. Forensics was able to prove it was murder since the arm had been cut off, not torn. No one was ever tried for the crime, though one suspect was conveniently murdered on the day of the inquest.
London, BritainPreparation is tricky here, but potentially very rewarding. Embalm body, treat with extra preservatives and stiffeners. Coat with wax. Carry to Madame Tussaud's.
Baltimore, United StatesJanet likes an idea used in The Wire: If you're in Baltimore, you can just nail gun them into one of the vacant row houses and cover them with lime.
Amsterdam, NetherlandsAnnablume recommends Amsterdam for convenience factor and the short commute with your victim:
In Amsterdam it's common use to dump bodies into one of the canals. You won't have to walk far, you will find a canal within short distance.
I guess this will work for Venice too.
Aberdeen, ScotlandBill suggests: Aberdeen's the oil capital of Europe. This means that lots of big pipes from the offshore installations get contaminated by Low Specific Activity scale - which is naturally occurring radioactivity that's sucked up from the reservoirs. They have to be brought ashore and treated in special facilities.
Drag your body (at dead of night, naturally), and stuff it into one of these pipes. No-one will come near it for ages.
The drawback is that your own skin will probably fall off on your way home.
Alternatively, using the same basic principle, you could drive the corpse up north, paint some luminous green spots on it and leave it exposed on the beach near the Dounreay reactor. Again, people will give it a wide berth.
AnywhereThe default solution for when your city doesn't have an obvious disposal spot: read the town's crime report, get a sense of where all the crime takes place, book a hotel far away from there, find a dumpster. Thank you, the very organized Miss Expatria.
Somewhat more difficult for the average mortal, Josephine Damian suggests CSI training should help with this problem. Enrol now.