Recommended video references:
Understand the Blockchain in Two Minutes
The Bitcoin and Blockchain Technology Explained
How the blockchain will radically transform the economy | Bettina Warburg
The Blockchain and Us (2017) | Manuel Stagars
Bitcoin: Where the Laws of Mathematics Prevail | Andreas Antonopoulos
06:47 What is a blockchain?
Blockchain 101 by Anders Brownworth
How Secure is 256 bit security?
Let alone the technology part of it, this cost of 51% attack explains the economic side of hacking the bitcoin.
19 Industries The Blockchain Will Disrupt