The Bitcoin Lightning Network is the transactional layer exclusive to the Bitcoin Blockchain. This layer allows two parties to transfer value among each other in a low cost and instant fashion, no matter where they are located in the world.
Why use the Lightning Network?
The Lightning Network can now be used to transfer fiat currencies (such as the US Dollar, Euro, etc.) internationally in a much faster and cheaper way than current alternatives and is growing to allow for the transfer of other assets as well.