Where can I find out what happened on a Saturday the 22nd in the world?

The problem is I don’t know what specific Saturday or even what month or year.

My Writing course recently took a trip to an Art Museum and we were asked to study a specific piece. The piece itself is a room (a cave more specifically), broken up into 5 sections. The last section had clocks on the wall representing different areas of the world. Each clock was stopped on the exact same time. One student brought up that each clock said “sam 22”. No one knew what it meant until my teacher told us that the artist was Swiss. I spoke up saying sam is most likely short for Samstag, German for Saturday. Something happened on Saturday the 22nd somewhere in time that made time stand still on the Earth. I need to find out what it means.