There are two Cavern Clubs in Ankh-Morpork.
The Cavern night club
A night spot in Ankh-Morpork frequented by the cooler sort of human and the nastier sort of troll. Glod Glodsson, for the first time in his musical career, wanted to duck out of a paying engagement, for fear of what might happen to a dwarf in this establishment. In practice, Chrysoprase, a fine upstanding Trollish community leader with a big investment in the club, has no prejudice against dwarfs as they use the same dollars everyone else has to, and if some of those dollars end up in the bar takings, that's an outcome he is personally happy with and if people is tolerant of dwarfs payin' for drink in my club, then there ain't no need for me to build a new rockery,
The Cavern night club Annotation
Based on the "Most famous club in the world": The Roundworld Cavern Club is a rock and roll club in Liverpool, England. Opened on Wednesday 16 January 1957, the club is where Brian Epstein first saw The Beatles performing, on 9 November 1961, and which has hosted an awful lot of huge bands before they were, well, huge, to wit: The Rolling Stones, The Yardbirds, The Kinks, Elton John, The Who and John Lee Hooker to name but a few.
The Cavern Club for dragon breeders
Totally unrelated to the nightclub, this is a select association for the breeders of pedigree swamp dragons, and welcomes anyone as a potential member who can afford to invest in kennels, kennelmaids, and a breeding stock of recognised pedigree breeds. Lady Sybil Ramkin and Brenda Rodley are among its leading lights. A related organisation, mentioned once in Men at Arms, is the Friendly Flame-throwers' Association.
The Cavern Club for dragon breeders Annotation
Loosely based on Roundworld Britain's Kennel Club, the organisation for people who are serious about pedigree dogs and all matters associated with them, which sponsors the seriously upmarket Crufts' annual dog show.