Board Thread:General Discussion/@comment-69.136.104.77-20170602103746/@comment-27794543-20170616220026

It was never directly explained but some possibilities include: Bombs only targeted major cities – if the island was far enough away, it would not be directly affected by the explosions. The buildings on the island may have been reinforced to protect from disasters. Also, while Grounders let most buildings/cities fall apart, ALIE kept the place running for the 100 years with the help of nomad Grounders.