1. It has been sold on underground forums since at least 2010.

2. One of the 28 giant underground tanks was found to be leaking in 2012.

3. I thought I would spend the rest of my life in this underground prison.

4. The anonymous website was a major sales point for illegal drugs and other underground goods.

5. The underground market for stolen consumer data is as hot as ever.

6. Hamas has since assembled thousands of rockets and built a system of underground bunkers.

7. Friday, when no workers were in the underground portions of the plant.

8. Some of the data became available in underground cybercrime forums.

9. The teams surveyed the underground rock by creating sound waves with a sledgehammer.

10. She pointed to underground forums where hackers swap and sell hotel and travel points for cash.

11. The underground cocaine economy gets credit for part of the economic boom.

12. Finding new sources of oil underground is an expensive and risky undertaking.

13. This free service will locate and mark all underground utilities in your proposed excavation site.

14. It will resume underground train service Monday only on portions of the Orange, Green and Red lines.

15. The music would be distributed through the Cuban underground on DVDs and thumb drives.