Etherscan
The Etherscan web site is a useful tool to look into the internal states of the Ethereum blockchain. You can use it to look up and review every transaction recorded on the blockchain and, by extension, the balance and history of every account. On its front page, you can see the latest blocks and the transactions within them (Figure 5.1).
FIGURE 5.1 Latest blocks and transactions in Etherscan
Wallets or exchanges can also display transactions to or from your account. Etherscan shows the accounts and fund involved, as well as whether the transaction is validated by blockchain miners (Figure 5.2).
FIGURE 5.2 Drilling into a transaction
Of course, as a developer, it is not enough just to have accounts and ETHs. We want to run the blockchain software, mine ETH coins, and execute our own smart contracts.