So I'm a little perplexed with Link To The Past. I know there is something obvious I'm missing here.

I'm at the top of the mountain, where you first enter the portal that takes you to The Dark World. Unless I'm mistaken, I can't see any way tp get down from here in the Dark World. I can use the Magic Mirror to get back to Light World. Regardless of whether I do that, once I've activated the mirror, I can't use it again and need to go back to that portal to enter the Dark Word again. So if I go back to the portal, I'm in the dark world again in an area I can't escape from.

How do I exlpore the rest of the map in Dark World? I have completed the castle and been transported to the Dark World and was able to explore somewhat (before I had the Moon Pearl) but had to come back to the light to get the Pearl. There is something really obvious here that I am missing. What is it?