Bitcoin is the very first of the Cryptocurrencies and it is currently ranked 1st in the cryptocurrency market.
It started around 2009 by Satoshi Nakamoto, a software developer. The main theme of Bitcoin is to generate a currency which is not relied on any central authority and can be transferred electronically.

The currency is not physically generated by a central bank and is not bound to any of the rules favoring the Banks and the investors. It is an independent and decentralized currency that can be obtained through an unique algorithm and the whole process is termed as Mining. It involves the computing power in a well expanded network.

Bitcoin has it's own limitation on number of coins that can be generated, which is 21million. Miners cannot obtain anymore than the limit. Anyhow, the coins can be obtained into minute parts and are known as Satoshi named after the Bitcoin's founder.



Characteristics of Bitcoin

Decentralization : As discussed earlier, Bitcoin is not centralized currency and is not controlled by an central authority. Each single machine/computer that participates in the mining process and transactions is a part of the whole network. The machines work as a team which makes it a network that is not centralized. So, even is a few of the machines in the network goes down or offline, the process continues without any halt.
Anonymous : Users can possess different bitcoin accounts which weren't linked to their personal details like names and addresses.
Transparency : Every transaction made in the network is stored in a general ledger called blockchain. So literally you can tell the number of bitcoins stored in an publicly used bitcoin account. 
Low Transaction Fee : Generally wire transfers or other payment transfer companies like paypal charge you anywhere between 2-5% transaction fee. This is not the case with bitcoin.
Faster transaction : There are scenarios where one should wait 3 to 5 business days to transfer money. But transactions with bitcoin takes only a few minutes.
So, Hope you got some significant details about the very first cryptocurrency. :)