Bitcoin started as an experiment in 2008. Most of the financial technology that has been developed since then has been based on or heavily influenced by Bitcoin.
Although Bitcoin has held the top spot in the market compared to the altcoins (all other digital currencies except Bitcoin), since January it has been rapidly losing market share against them.
Despite this fact, Bitcoin still remains the most liquid of all of the digital currencies. In every country in the world you will find a place to buy and sell Bitcoin.