The astronaut everyone loves, cant remember his name, demonstrated this not too long ago by being pretty deep below water level where the pressure is just...much greater than on a beach.

He shook a soda pretty vigorously, and then cracked it. Since the pressure was so high down there, the pop only slightly fizzed.

This is also why deep divers have to surface slowly, or spend time in a hyperbaric (pressure) chamber if the need to surface quickly. The nitrogen gas in their blood/tissue expands as they go up, and needs to be done slowly or you get "the bends". Think meat balloon on a cellular level. Can be fatal, or cause life long problems. One guys body swelled up like crazy after an emergency deep dive surfacing (lost his air hose) and survived; though the hyperbaric chamber didnt really help him like it can others - he stayed unfortunately very swollen. But at least he didnt die. The bends are very painful, im told.

All because of gasses in liquids at varying pressures.