The Dome was a gigantic glass dome placed over Springfield by the EPA. It is an almost impenetrable object that was put over Springfield due to it being the most polluted town in the World. It was a crisis so bad, it had its own name and theme music, Trappuccino.
The Dome could easily crush people when coming down, as one unfortunate person found out. It had to be transported by loads of helicopters with suction cups holding it up.
It could only be damaged after numerous repeated attacks. There would have been a way to destroy a hole with Professor Frink's Acid Shooting Ray. However, this was on the other side of the Dome. Repeated attacks, such as Stampy hitting it, could crack the Dome though. The Dome also had a massive television screen, invisible at first, that Russ Cargill, head of EPA, could communicate to Springfield on.
The Dome was finally destroyed by Homer and Bart on the day Springfield was to be blown to smithereens. Homer rode a motorcycle around the Dome with Bart throwing the bomb out of the hole on top (which was previously plugged up). The bomb destroyed the Dome, but not the town itself.
A long time after the dome was destroyed, Mr. Burns made another one. He was going to lower it onto Springfield, but everyone reminded him it had already been done and they could just dig themselves out of the dome. Mr Burns then left.
- It is unknown why the residents of Springfield didn't dig a hole under the dome. A possibility is that the Springfield residents weren't thinking clearly, and just tried to break out of it, rather than digging a hole, or there was a lack of shovels. However, Russ Cargill of the EPA ordered death squads to watch the dome's perimeter, so perhaps anyone who did think to escape would have been deterred.
- The plug only appears when it is removed for the bomb to be put in. It is invisible before that; most likely an error.