I found a link to the Viral Nova article through another user on the RPGBA, and I liked the content of the original article so much, I tracked down Wikipedia articles (and one Slate article) linking to more information about each.

Edit: Thanks to The Troll Dens for pointing this out.

Credit goes to Viral Nova for compiling the original list — this is just for my reference, including handy links to more information about each location. Incidentally, it seems that the “Wonderland” in China was demolished earlier this year, and I couldn’t find a decent source for the Kabayan Mummy Caves.

Here’s a link to the original post on Viral Nova:
Link: 10 Nightmarish Places On Earth

1. Door to Hell
Located in Turkmenistan
Link: Wikipedia

2. Island of the Dolls
Located in Mexico
Link: Wikipedia

3. Centralia, Pennsylvania
Located in United States
Link: Wikipedia

4. Muynak Ship Graveyard
Located in Uzbekistan
Link: Wikipedia

5. Kabayan Mummy Caves
Located in the Philippines
(Couldn’t find a good source)

6. Hill of Crosses
Located in Lithuania
Link: Wikipedia

7. Cincinnati Subway, Ohio
Located in United States
Link: Wikipedia

8. Akodessewa Fetish Market
Located in Togo
Link: Slate

9. Wonderland Amusement Park
Located in China
(Razed in May 2013)
Link: Wikipedia

10. Catacombs of Paris
Located in France
Link: Wikipedia