The specific price of BTC relative to fiat currency at any given time depends on the rate set by specific exchanges, and the listed all-time high price or price at any given time depends on the particular data set referenced. Though Bitstamp does not list the highest all-time bitcoin price of any exchange (Bitfinex, for instance, listed bitcoin at $19,891 on December 11, 2017), its data stream represents one of the longest-operating bitcoin exchanges in history.
The all-time high mark set today represents a major milestone in a bitcoin bull market that started in early March 2020, when the price rallied from a low in the $3,000 range. Since then, it has reached more than six times its value in less than nine months. Bitcoin set an all-time market capitalization high on November 17, 2020.
Though bitcoin is a monetary system in and of itself, that is not reliant on value relative to USD or any other fiat system, the USD price of 1 BTC is a popular metric for signalling the growing acceptance of Bitcoin. By many measures, bitcoin has been the single-best performing financial asset in the world since it was introduced by Satoshi Nakamoto in January 2009.