Bitcoin, Ethereum and Litecoin value graph look very similar I don't know much about cryptocurrencies, but I was looking at the Coinbase value graphs of bitcoin and ethereum, and noticed that even on one day, every single dip and peak affect all three currencies displayed. Why is that?

Value graph
The prices of basically all altcoins follows that of Bitcoin's. So generally when Bitcoin goes up, so do altcoins', when it drops, so do altcoins'. This is generally because altcoins are primarily used as a way for people to get more Bitcoin.