Amazing Underground Worlds From Around The Globe

#12 is a stunner.

1. Naples, Italy

2. Paris, France

3. Prague, Czech Republic

4. Moscow, Russia

5. Shanghai, China

6. Budapest, Hungary

7. London, United Kingdom

8. Pyongyang, North Korea

9. Seoul, South Korea

10. Berlin, Germany

11. Tashkent, Uzbekistan

12. Stockholm, Sweden