Blockchain.info

Bitcoin Block Explorer is an open source web tool that allows you to view information about the blocks, addresses, and transactions created by Bitcoin.

OmniExplorer is a Block Explorer for the Omni protocol which is created and maintained by the Omni Foundation. It allows you to query address balances and transaction data on the Omni protocol. Over time additional statistics, information, tools may be added to assist the community.

Bitcoin block reward halving countdown. The Bitcoin block mining reward halves every 210,000 blocks

BitcoinChain.com is an analytics and monitoring platform that provides both live statistics and historical data within the Bitcoin ecosystem: Blockchain Explorer, Exchange Markets and Mining Pools. Also the Platform has recently started to provide a Bitcoin Wallet service. Launched in January 2013, the platform provides Block Explorer service which allows for viewing detailed information about bitcoin addresses, transactions and blocks.