Everyone knows about hidden worlds. The denied-about-its-existance-by-TNT Jelly World, Fyora's famed Hidden Tower, and so many others. So, below is the link, name, location (if there is one), and a quick description about the various hidden places in Neopia.

Name: The Hidden Tower
Link: http://www.neopets.com/faerieland/hiddentower938.phtml
Description: Run by Fyora, the Hidden Tower is a place where expensive and uber-rare items.
Location: Go to Faerieland, then enter Faerie City. To see where you click, find the multi-colored box in the screenie below.


Name: Fungus Cave
Link: http://www.neopets.com/pirates/funguscave.phtml
Description: Here is where you take your Krawk petpet to feed it fungus so that it can turn it into an actual Krawk pet.
Location: Go to Krawk Island. To see where you click, find the multi-colored box in the screenie below.


Name: Jelly World
Link: http://www.neopets.com/jelly/
Description: Jelly World is just like any other world. There's colouring pages, the Giant Jelly, Jelly Foods, and afew other things.
Location: None. The only way to get to this place is via a direct link, or by the exact url.

Name: Draik Nest
Link: http://www.neopets.com/medieval/draiknest.phtml
Description: This is where you take your Draik Neggs to hatch so that they turn into real Draik pets.
Location: None. The only way to get to this place is via a direct link, or by the exact url, as far as I know.

Name: Jelly World Neoboard
Link: http://www.neopets.com/neoboards/boardlist.phtml?board=18
Description: This is where you can discuss Jelly World! YAY!
Location: None. The only way to get to this place is via a direct link, or by the exact url.