The bitcoin is a form of cryptocurrency and originated from dissatisfaction with the regular monetary systems. Blockchain is a technique that uses the bitcoin system. The blockchain technique appeals to the imagination a lot and people think it can be used for all kinds of transactions. In this talk, the position of our money is first discussed and then (in about 5 slides) some basic concepts of cryptography, because without it the whole is incomprehensible. Then we are ready for the bitcoin and the blockchain automatically comes forward. Finally, we will discuss alternatives that bypass many objections from bitcoin and blockchain, such as the Libra from Face book and an alternative described in a white paper from 2016 by Jacob Wijngaard and the speaker. The value development of crypto coins and not all look-a-likes of the bitcoin are discussed.