At its core, the blockchain is a chain of information-containing blocks arranged according to certain rules. Its peculiarity is that one block may be the previous one for any number of subsequent ones. In other words, the chain can branch out infinitely. At the same time, getting access to any of the blocks, a person may not know about the presence of other branches.
For the first time, blockchain technology was used in the Bitcoin system. It can serve as a basis for building decentralized business platforms in almost all areas.