An online tool for exploring the blockchain of a particular cryptocurrency, where you can watch and follow live all the transactions happening on the blockchain.
Block explorers can serve as blockchain analysis and provide information such as total network hash rate, coin supply, transaction growth, mining or staking pools data, transactions, and more. The type of data being displayed on these block explorers is what we call on-chain real-time data/metrics.
For the Cardano blockchain, here are some block explorer websites that we recommend: