The block explorer is one of the most important tools in the crypto enthusiast's toolbox. Using their online interface, you can search a blockchain and retrieve data about transactions, addresses, blocks, fees, and more. It depends on the architecture of the blockchain it serves to determine what type of information each block explorer provides for a particular blockchain.
There is no single block explorer that can retrieve information about Bitcoin and Ethereum; instead, you would need a Bitcoin block explorer and an Ethereum block explorer. There are, however, some sites that host block explorers for multiple blockchains. In addition to etherscan.io, blockstream.info, blockchain.com, and CoinMarketCap, other popular Bitcoin and Ethereum block explorers include etherscan.io, blockstream.info, and blockchain.com.

A block explorer is a vital tool in the world of blockchain technology, serving as a transparent window into the inner workings of a blockchain network. It allows users to explore and trace the details of transactions and blocks on a given blockchain. Providing real-time and historical data, a block explorer displays transaction information, including sender and recipient addresses, transaction amounts, and timestamps. It also reveals block details such as size, hash, and the number of transactions contained within. This tool enhances transparency and accountability within decentralized systems, enabling users to verify transactions, track fund movements, and monitor network health. Users, developers, and researchers utilize block explorers to gain insights into the integrity and efficiency of a blockchain, fostering trust and reliability in the decentralized ecosystem.