Learn Italian: Benché l'ambiente sia selvaggio, la grotta è sicura. - Even though the environment is wild, the cave is safe.

Benché means "although" or "even though." In Italian, conjunctions of concession like this introduce a dependent clause and always require the subjunctive mood. Because we are talking about the present, we use sia, the present subjunctive of essere.

If benché requires the subjunctive, why does the second part use the normal indicative è?

The subjunctive is only triggered in the specific clause introduced by benché. The second half of the sentence, la grotta è sicura, is the main clause and stands on its own. Main clauses almost always use the regular indicative mood.

Could I use sebbene or nonostante instead of benché?

Absolutely. Sebbene and benché are practically identical in meaning and usage. You could also use nonostante. All three mean "although" or "even though," and all three require the subjunctive, so the verb would remain sia.

I see selvaggio ends in -o but sicura ends in -a. Why the difference?