What is The Blockchain?
As mention earlier in “What is cryptocurrency?” The Blockchain is the answer to destroy “Centralization”. The opposite of “Centralization” is “Decentralization”. What does it mean? Well in case of FIAT it is a central bank or a ledger that keeps the gold or value of money. A place which is nothing more than a middleman or thirth person(‘s). When such place become corrupt you can’t rely on it.
A blockchain is a time-stamped series of immutable records of data that is managed by a cluster of computers not owned by any single entity. Each of these blocks of data (block) is secured and bound to each other using cryptographic principles (chain). The blockchain network has no central authority, it is the very definition of a democratized system. Since it is a shared and immutable ledger, the information in it is open for anyone and everyone to see. Hence, anything that is built on the blockchain is by its very nature transparent and everyone involved is accountable for their actions.
The blockchain is a simple yet ingenious way of passing information from A to B in a fully automated and safe manner. One party to a transaction initiates the process by creating a block. This block is verified by thousands, perhaps millions of computers distributed around the net. The verified block is added to a chain, which is stored across the net, creating not just a unique record, but a unique record with a unique history. Falsifying a single record would mean falsifying the entire chain in millions of instances. That is virtually impossible.
So The Blockchain is decentralized or an open ledger. What means that it is like an open digital landscape. But how is it possible to keep right registrations? By a digital landscape that is host by a global network of computers (nodes) that shares the same ledger. All share the same data from the beginning and once something change in the data the whole network must do the same verification. If one (node) is corrupt and try to steel, hack or unauthorized try to change data it can’t match with the rest of the network. So the false node will be seen as a hack and wont be acknowledge. This way it is “Decentralized” and isn’t a middleman/third person anymore and nothing or nobody to regulate.
On Wikipedia you can also find more explanation.