Coiners like to argue that, devoid of government interference, BTC is free of manipulation. Like many statements by devotees, this falls somewhere between misleading and mendacious.
Clearly, the price of any asset depends on the perception or maybe even whim of the people who trade it or use it.
So-called cryptocurrencies have been in the news quite a lot recently. Presumably, this was because Bitcoin closed trading on 1st September at US$4,904.