People believe bitcoin is backed by nothing. I think that is not the truth. I believe bitcoin is actually backed by people themselves. It is backed by none other than just you. We all witnessed the price has been fluctuating by all those FUDs and bad news. The price changes by emotion and non logical facts. I believe you hold bitcoin no matter what happened and would happen, and believe it is backed by all of us, it would make a history. 
It's not backed by anything unlike the traditional currencies that are generally supported by gold reserves. Since cryptocurrencies are a different kind of currency, it's rise and fall are affected by other factors. That's why when we hear negative news, banning of cryptocurrency activities in some countries, and dipping in value of some coins, especially Bitcoin, it somehow affects the market trends that, in turn, affects other coins in the market. That's actually one of the things that an investor or trader must work with to be able to be successful in this market.