Ten years on, there's still a Hurricane Katrina bicycle tour around New Orleans. After 70 years, Hiroshima and Nagasaki are as popular as ever.
After 100 years, school trips still visit Flanders Fields. Around the world, visitors flock to killing fields. Choeung Ek is a must-see in Cambodia. It must be ticked off. Pompeii, perhaps the world's oldest disaster-tourism site, has been open to visitors since 79AD.
Suffering intrigues. Rio now has rather-you-than-me homestays at its favela slums. Following in the lead of escorted Dharavi slum tours in Mumbai, China offers "hutong" excursions.
The small Louisiana town of Gibsland stages an annual re-enactment of the 1936 murder of the notorious criminals Bonnie Parker and Clyde Barrow. It's part of the "Bloody Bonnie and Clyde Adventure Trail", taking you to places where they shot people.
At the anniversary re-enactment festival there is a look-alike contest for the out-of-towner most resembling one of the Texas Rangers who caught up with the infamous duo and killed them with 140 rounds. You can see the bullet-riddled Ford V8 "death car" in Nevada, as well as Bonnie's blood-spattered "death dress" and "death gloves". One museum claims to exhibit Clyde's trigger finger.
In California, you can go on a tour of the Sacramento home of serial killer Dorothea Puente and take a walk around the back garden where she buried seven victims.
We cannot resist carnage or catastrophes and tourism operators can't resist commercialising death. The ghoulish sells. Disaster is a sure-fire revenue stream.
Why, apart from income? And why is standing on the Wounded Knee battlefield somehow more acceptable than standing in the Somme? Why should Gettysburg be more educational, less tasteless, less inappropriate and less harrowing than Goose Green?
What's the draw? Quirky souvenirs? The need to get a memorable selfie? Something to impress. A memorable post? Like doing a thumbs-up in front of a Holocaust memorial or namaskar-ing in front of the Enola Gay?
What's so attractive about dystopia? What's the big deal? Is it just being grateful for still being alive, or being part of some global atavistic survivor guilt complex?
No one knows. I met a young man at Ground Zero who had his own odd reason for visiting these places. I asked him why he was there. He said to steal toilet paper.
He collects it from famous places.
He has a roll from Dealey Plaza.