My first day in London (never been to europe before), I used a toilet and I was trying to figure out how to flush. There was a bright red rope next to the toilet so I pulled it and an alarm started going off and I freaked out. Thankfully I saw a button that said something like reset alarm so I hit it quickly.

In my defense the actual flush button was on the wall behind the toilet. The wall was grey and the button was also the same grey and flush with the wall. I thought it was some kind of panel.