Now, we will look at the overall structure of the Bitcoin blockchain header in the following diagram:

In this example, Block 16 represents the previous block's hash and consists of the timestamp of creation, the transaction root is also known as the Merkle root, and the nonce is the algorithm-cum-counter that has to be verified. All of the hidden information on the transactions is hashed again, and that hash is captured in Block 17. It consists of the previous block's hash, the timestamp, the Merkle root, and the nonce.

In the sections for Data 1, Data 2, Data 3, and Data 4 in the preceding diagram, all the data is paired and hashed multiple times. Thus, the data keeps going in the upward direction until it gets to one final hash. These blocks keep moving and the entire Merkle tree is formed by the transactions that are captured in the blocks. This is what makes it so strong, robust, tamperproof, integrated, and immutable. This is the beauty of blockchain.