Layer 2 Blockchain solutions are built on top of an existing Layer 1 blockchain (like Ethereum) to enhance scalability and transaction speed while retaining the security of the base layer. These solutions offload transactions from the main chain (Layer 1) to a secondary layer, which can process transactions more quickly and efficiently. After processing, the results are recorded back on the main chain. Common Layer 2 solutions include state channels, sidechains, and rollups. They play a crucial role in scaling blockchain networks, enabling them to support more users and transactions without compromising on decentralization or security.