Answer:
The Titanic is still here.
I hide in a dark tunnel awaiting my time. I can only be released by pulling back. Once released I may do unstoppable damage.
You throw away my outside, you cook my inside. Then you eat my outside and you throw away my inside. What am I?
A necessity to some a treasure to many I'm best enjoyed among pleasant company. Some like me hot some like me cold. Some prefer mild some like me bold.
I start new then become old. Start clean but become dirty. I usually start big then become little. What am I?
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.