Watchamacallit

I took this photo in Amsterdam, Holland. Three Saint Andrew's Crosses were depicted on watchamacallit. What is the name of the metallic thingy on the ground next to a trash can? I have no idea even in the language of my mother country. Come to think of it, there are so many things in the world that I don't know their standard name. For lack of a better example, but one of my mentors had told me about a clogged toilet. He said there's a special device to fix a clogged toilet. The device is normally made of a plastic long handle with a rubber cup, and it's called plunger. He said this is very important word, be sure to remember the name. If he say so.