I used to play this at max volume and may account for my less than stellar hearing.

Had a conference there.
There is a rebuilt casino but it's way more modern, so the didn't try to reproduce the beautiful building in your picture. That's where most of the papers were delivered & presentations made.
One afternoon, I walked over to The Grand Hotel, which had been recently reopened after renovations.
I walked the halls, just imagining where Deep Purple holed up to record Machine Head.
For a fan, it was a great experience.

What a month of rock and roll touring for Zappa.

When Frank Zappa was nearly killed on stage by a jealous boyfriend

The figure of “jealous lover” has been a constant in literature and pop culture. From rom-com to thriller, each genre has exploited this concept to expose the dramatics of romantic love. When we witness an on-screen theatrical face-off between the insecure boyfriend and the crush, it may tickle us to the core or make our eyes roll thinking “these don’t happen in real-life!”. However, we must not forget that art and literature are not always fabricated, they draw largely from real incidents. The story of Frank Zappa’s fateful night in London is one such example.

On December 10, 1971, The Mothers of Invention were playing at the Rainbow Theatre in London. As the versatile lead singer, instrumentalist and composer Frank Zappa started a cover of The Beatles song ‘I Want to Hold Your Hand,’ he was attacked by a member of the audience. 24-year-old Trevor Howell emerged from the crowd like a shooting meteor and flew at Zappa before he could register the angered audience member. Zappa fell off the stage as a result of the attack and landed on the concrete-floored orchestra pit.

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In his 1989 autobiographical book The Real Frank Zappa Book, Zappa while re-tracing the scarring incident said, “The band thought I was dead…My head was over on my shoulder, and my neck was bent like it was broken. I had a gash in my chin, a hole in the back of my head, a broken rib, and a fractured leg. One arm was paralyzed.” The 15-foot fall also crushed Zappa’s larynx which affected his vocal range making him transform into a low and husky style. It could have been so much worse for the singer.

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December was indeed a doomed month for Zappa and his band. A week prior to this event, a crazy fan fired a gun during the band’s performance at the Montreux Casino in Geneva, Switzerland. As if this wasn’t enough, the venue’s heating system blew up which started a devastating fire. It engulfed the band’s instruments, injured several people and burnt down the venue to the ground. Two back-to-back incidents affected the band deeply. Following the Rainbow theatre misadventure, the Mothers of Invention had to cancel their live performances and couldn’t hit the roads for six months.

Zappa recovered a great deal from the shock but was bound to a wheelchair for almost a year and suffered from chronic back pain because of the ordeal. His fractured leg though became functional, was shorter than the other one. But Frank Zappa, being the creative genius he was, did not miss this opportunity to write a song named ‘Dancin’ Fool’ which had the following lines: “Ì don’t know much about dancin’, that’s why I got this song. One of my legs is shorter than the other and both my feet’s too long.”

https://faroutmagazine.co.uk/frank-zappa-attacked-by-fan-london-1971-death/