"Yes, the castle is popular among tourists."
Translation:Igen, a vár népszerű a turisták között.
Yes, it is. Otherwise it would sound like we are talking about popular tourists in an incomplete sentence. "the castle among popular tourists"
But the main reason is that it is yet another case, similar to those general statements, where English usually does not use a definite article, and Hungarian usually does.
But if you do it like this:
"Igen, a vár turisták között népszerű"
Is the a still necessary before turisták?
If not necessary, at least recommended.
In general, Hungarian prefers using an article even with plural nouns that are not definite. Just think of those general statements:
"Lions are animals, too."
"Az oroszlánok is állatok."
The same deal is going on here.
But it was "among tourists" not " among the tourists". Can we consider it is in general?
I guess the more similar word to castle kastély is not wrong but perhaps better used as a translation for palace. Or would that be palota?
I would say "palace" is "palota", and "kastély" is an upscale "castle".
A "vár" is usually a complex upon a hill or mountain, surrounded by a thick wall. It can be several buildings, even streets, within a "vár".
A "kastély" is more like one very elaborate building (maybe with its service buildings). It can be like a palace, and it is not necessarily on a hill. It can be anywhere.
And a "kastély" that is on a hill can be called a "várkastély".
Also, a "vár" serves to protect from the enemy. A "kastély" is the home of the very rich, typically not heavily fortified.