Holograms

No doubt a retro-themed bar with retro-themed entertainment...

Incidentally, what does it tell of the population demographics of San Francisco that this bar has so many people in Starfleet uniform present? Was McCoy/Spock's only hope of finding an unscrupulous civilian pilot really dependent on him going to a Starfleet-frequented joint? Or are there no other sort in SF?

Timo Saloniemi