Bitcoin continues to attract enormous attention from investors, but it is not the only cryptocurrency in existence. As fears grow that Bitcoin's rapid growth was little more than a bubble, more and more people are starting to consider its rivals.
There are now hundreds of cryptocurrencies and, while they have significant differences, all are based on blockchain technology.
A blockchain is a method of record-keeping that uses a network of individual computers to store a log of transactions, and verify new transactions, without the involvement of a central organisation such as a bank.
The top five largest currencies change regularly as prices of individual currencies fluctuate, but these are some...