Although float tanks may seem like a recent phenomenon of the 21st century due to their recent popularity boost, it may surprise you to find out they originated in 1953. They were developed by Dr. John Lilly as part of a hypothesis he was working on. The scientific question at hand was more of less: "What happens if you remove the stimulation of the outside world?"
After a great deal of tweaking and experimentation, Dr. Lilly had a his experiment running and fully functional by 1954. I can imagine that there was a lot of fine tuning that went into his early visions of a float tank, and I'm sure they looked a whole lot different more than 60 years ago. Fortunately he got the ball rolling, and modern technology has taken these incredible devices to new levels.
In fact, just take a peek at the difference between an earlier generation float tank, and a more state of the art, modern float tank ...
Let's be serious, which one would you rather hang out in for an hour or two of relaxation?