Cavitation bubbles, when correctly tuned, may provide interesting mechanical and chemical effects to their surroundings owing to their violent collapse. Such an event may produce high-speed liquid jetting, extreme heating, as well as pressures of thousands of atmospheres. These phenomena are responsible for the severe erosion harming hydraulic machinery, but they also present interesting traits to harness in cleaning, sonochemistry, biomedical applications, among others. Here, we present experimental observations on the high pressures produced by spherically collapsing cavitation bubbles. Filming at 10 million frames/s allows for the disclosure of details on the high pressures (kbar-level) in the liquid near the bubble in its final collapse stages that precede the shock wave emission, confirming the century-old prediction of Lord Rayleigh.