Cave Expedition

The Cave Expedition is an activity that began on January 22, 2010 and ended on January 28, 2010. It was confirmed on the What's New Blog and the Club Penguin Times Issue #223. The point of the activity is to explore the caves and the underwater. The free items were a Miner's Helmet at the Mine and a hidden pin (The Amethyst Pin) that could be found if you dug all the pieces of it using the Jackhammer 3000 or the shovel. The expedition consists of four rooms: The Mine, The Mine Cave, the Hidden Lake and the Underwater (which is for members only). The caves have been opened again on March 15, 2010, assuming that they are safe.

What To Do

Spoiler warning: Plot and/or ending details follow. Click “Expand” to view spoilers.

When you got inside of the Mine Cave, you would get your helmet out and start jackhammering. You would find a crystal piece each time. You had to move and jackhammer 4 times. Then, you would unlock the Hidden Lake, where you would find a Deep Sea Diving Suit for 50 coins (only for members). Go into the lake and you would see a entrance to the Underwater. Then, you would get the free Coral Reef Background and your expedition was done.

Spoilers end here.

Gallery

The Amethyst Pin, which can only be achieved either from playing the treasure hunt in the cave or cheating.
The Underwater.
The snowball powered electricity generator in the hidden cave.
The login screen for the activity.
The entrance to the Caves being blocked by a rockslide.

Trivia

There was a member item (a diver suit) for sale at the Hidden Lake that cost 50 Coins.
The room returned as said in the Club Penguin Times March 15, 2010, along with the new game, Puffle Rescue.
Some penguins thought that it would be the location of a new Aqua Grabber level, since there was a broken Aqua Grabber submarine at the Hidden Lake.
This is thought to be where the missing puffles are heading to, due to a yellow puffle in the entrance. This is most likely true because Yarr, Keeper of the Boiler Room, and the Keeper of the stage went missing on March 4, 2010, and Yarr was found inside it and the other puffles returned on March 11, 2010.
It is apparently connected to the new Puffle Rescue mini-game released on March 15, 2010.
The Mine Cave is the Only Room on CP to have a permanent free item, the Miner's Helmet...To do this, go to the mine cave entrance and walk up to or near the jackhammer.