Today I was in the library when they observed the two-minutes silence for Armistice day. The start of the silence was marked by a bell. A man sitting nearby asked what the bell was for and it had to be explained to him. Once he knew what it was, he stood up for the duration of the minute.
The end of the minute wasn’t marked by the same bell, but I thought I heard a bell that rang very faintly in the distance but I wasn't sure. Of course, being in a library, it was hard to tell when the silence had ended. It was only when people were being served at the desk was I sure that we’d finished.
About half an hour later, the man who’d stood throughout the silence got up to leave. He balanced out his earlier respectful silence by knocking over his chair.