A company in Japan lost $473 million of bitcoins. The company is called Mt. Gox. It lost 850,000 bitcoins. Mt. Gox was one of the world's biggest Bitcoin companies. It said hackers stole the money. The CEO apologised to investors. Thousands of people are angry because they lost their money. Bitcoin is a virtual currency. It might replace paper money and coins. People only use it online. Anyone can buy and use bitcoins. You don't need a bank account.

The collapse of Mt. Gox was not a surprise. There are no laws to control Bitcoin. Mt. Gox was an accident waiting to happen. People say Bitcoin will recover and be stronger. There will be a better system with tighter security. Countries might make laws to make Bitcoin safer. An expert said: "If you look at the short history of Bitcoin, there has been a series of bubbles, busts, hacks and thefts. After every single event, Bitcoin [was] stronger."