A bubble chamber uses a liquid that reacts to charged particles by developing small bubbles. As the particle passes through the liquid the bubbles form tracks that can be photographed. Particle physicists used to use bubble chambers to study the reactions of elementary particles. I did my Ph.D. using a the Big European Bubble Chamber (BEBC) at CERN in the 80's. Bubble chambers became less useful when event rates become very high. I have discovered that they have become public art at particle physics labs.
Fermilab has taken a photo of the 15 foot bubble from a different angle during the winter that looks a scene from Stars wars.