In November of 1968 my buddy Robin and I sailed to England on the Empress of England, spent part of the winter there, and on January 21, 1969 we went to a small club in London called Klooks Kleek where we saw John Mayall and his band crank out the blues.
The lead guitarist in the band at that time was Mick Taylor, who several months later would join the Rolling Stones after Brian Jones died in his swimming pool.
Below is my ticket stub from that night.
Just recently, while going through the bowels of eBay, I found something that I thought was fairly mind-blowing (for me, at least), and which I bought because the urge to have it overcame me.