When Bitcoin mines its last block, it means that the maximum number of bitcoins that can be created (21 million) has been reached. The network will not stop working as it is decentralized and maintained by nodes all around the world. Transactions will still be processed and verified, but no new bitcoins will be generated.

However, this event is not expected to occur anytime soon, as current projections indicate that the last block will be mined in the year 2140. Until then, the network will continue to operate as usual.