| Underground burial chamber |
| Growths on the grapevine |
| Pioneering underground publication of the 1960s |
| Aquarium growths |
| Paris underground system |
| About 600 miles of underground passages near Rome |
| Ancient underground tunnel |
| One of the founders of the underground comix movement: 2 wds. |
| Paris underground |
| Tree trunk outgrowths |
| Underground" director Kusturica |
| Trains underground |
| Coffin of the Underground Railroad |
| Child actor with a pizza-themed Velvet Underground cover band |
| Member of an underground colony |
| One-named singer with the 1960s Velvet Underground |
| Part of an underground network |
| NYC underground system |
| Gr. underground movement in W.W. II |
| Underground explosions |
| Goes underground, maybe |
| Underground experiment, for short |
| Yearly tree growths |
| Underground utilities conductors. |
| Kept underground, maybe |
| Greek underground group. |
| Carlsbad ___ (national park with underground chambers) |
| Underground worker |
| Underground passageway |
| One with an underground sense of humor? |