The cave is towards the western side of the national park, making it an ideal day trip from Manchester.
Your ticket includes entry to a small exhibition on the history of the cave, but the main attraction is the guided tour. You'll be taken approximately 310m into the cavern, where you can enjoy sights like this:
The cavern is said to be named after a 15th-century outlaw called Poole, who used it as a hideout. In those days, the only way inside was to crawl through a low tunnel. After robbing travellers, it was easy for Poole to disappear into the cave. This eventually backfired on him, when the locals became so sick of his crimes that they sealed up the entrance and left him inside to die.
The cave has been a tourist destination since at least the 1580s, when it was visited by Mary, Queen of Scots. Deep inside there's a rock called Queen of Scots Pillar, which she is supposed to have been especially impressed with. However, our guide said that this part of the story is probably a myth. As she suffered with severe rheumatism, it seems unlikely that she would have spent hours crawling through cold water to reach this point.
Thankfully, this is no longer necessary. It's a nice, easy tour, with no need for helmets or any special gear.
There's an easy path although there are some steps