I had the privilege to to see Rare Earth in concert at the Mid-South Colosseum in Memphis, February 1970. The show was called the 1st Memphis International Rock Festival. In addition Rare Earth there was Chicago, Mountain, Pacific Gas & Electric and a bunch more.
The most memorable part of the show came during Get Ready. There was a big storm going on outside and lighting hit knocking out the power. Of course all the lights went out, all the sound equipment died and 15,000 people where left standing in total darkness.
Just as people were starting to get scared you could hear, thump, thump, thump, from the stage. Peter Hoorelbeke, the only one who didn't need an amplifier, was playing a drum solo in the dark. Everyone stopped moving around and listened to him play until the power came back on.
Not only was this a great demonstration of musical talent, it also probably saved some injuries in the crowd.