16 years ago, Satoshi Nakamoto releases the Bitcoin white paper to the cryptography mailing list, marking its official introduction into the world.
Satoshi introduces Bitcoin as an electronic cash system with several important properties: double-spending is prevented with a peer-to-peer network; no mint or other trusted parties; participants can be anonymous; new coins are made from Hashcash style proof-of-work; the proof-of-work for new coin generation also powers the network to prevent double-spending.
The paper is available at:
http://www.bitcoin.org/bitcoin.pdf