The Winklevoss twins will launch an American bitcoin exchange called Gemini. REUTERS/Lucas Jackson

The bitcoin ecosystem has never been more diverse, with multimillion-dollar companies trying to take the digital currency "mainstream" and hackers dreaming up a new blockchain-powered social order.

We've spent the past several weeks speaking to CEOs, journalists, investors, and others in the bitcoin scene in search of some of the most exciting startups and projects out there.

We've drawn on the expert advice we've been given. We've also looked at funding, to see which crypto companies are turning financiers' heads. And lastly, we have hunted ourselves for the most ambitious projects out there, taking the basic principles underpinning the decentralised digital currency in the most outlandish — and exciting — directions.