The Swedish Bars
You have no doubt seen these along the walls in Classic Gyms but didn't know what they were - so now you do. The Swedish Bars (also called Stall Bars or Gymnastic Bars) were created by the Swedish physical training pioneer Pehr Henrik Ling back in the 1800s (a derivation of the climbing ladder).
They soon became a standard piece of gymnastic training equipment in physical culture gymnasiums, YMCAs and especially in the military. The Swedish Bars are used to build flexibility as well as to perform a variety of exercises, most notablly abdominal work.