Comment by adastra22

Not quite.

You use either “a” or “the” when you are specifying a class of things. “Our town has a castle” could be any castle. “Our town has the castle” would be a bit more rare and sounds weird as a general statement, but is valid in certain circumstances. “The castle” here means that the castle is something, or connected to something we have already been discussing and I’m referring to it, so the “our town” must be the new information. Like maybe we are discussing what we should do when you next visit, and I suggest seeing some particular famous tapestries. You say “wait, isn’t that castle [in which the tapestry is displayed] in Edinburgh?” And I reply “no, our town has the castle.”

You don’t use any article at all when what you’re talking about is unique. For example, “our town has Neuschwanstein Castle.”

Edit: or there is something which follows, e.g. “our town has the castle where they filmed Braveheart.”