Crystal Ruins

Crystal Ruins, also called CR, located in western Winden. It used to be the dungeon after Winden Forest, but was moved. Crystal Ruins and Crystal Castle were the first dungeons to be added to Winden after its release. It was once the hardest non-event and non-set-level dungeon in PMU 7 (later beaten by Mt. Barricade).

The Pokémon in this dungeon are mainly in the level range of 35-41, but Gastly are lower than 18, and Regice is level 60.

Scenery
The walls are crystal-like and dark blue with some green crystals scattered around. The floor is a light-blue stone, with some bluer rocks here and there. There is a darkness surrounding the player after floor 10, with the darkness eventually getting larger and larger, obscuring vision more and more. It is usually hailing.

There is a Sealed Chamber on floor 15 with chance of having Clear Silk.

Pokemon
All Pokémon in this dungeon spawn naturally and randomly. There is no guarantee that a player will encounter a Regice on their journey. There are Ghost, Water, and Ice types here.
 * Gastly (14f+)
 * Spheal
 * Haunter
 * Shellder
 * Sealeo
 * Swinub
 * Piloswine
 * Snorunt
 * Glalie

Regice
From 11F and upwards, everytime the player enters a new floor, Regice has a chance to spawn, although in rare cases (be it Honey or Spawn Traps or just spawning) he will make a surprise attack. He will drop Ice Diamond, TM Ice Beam, and a Regice Heart Slate.

He is at level 60 and has the following moves:
 * Ice Beam
 * Zap Cannon
 * Hyper Beam
 * Icy Wind

The boss of Crystal Ruins is a Mamoswime, he doesn't drop anything and has the following moves:

 * Ice Beam
 * Bulldoze
 * Dig
 * Take Down

Before Battle:
Who are you to infiltrate this place!?

I am the mighty Mamoswime, and i shall not let you pass! Prepare to be squashed like the insect you are!

Dungeon Objectives
The main goal is like most other dungeons, to complete it and beat the boss(es). TM Ice Beam is also a very valuable and wanted item. Regice can drop its Heart Slate, which allows it to be summoned in a dungeon if Regice's Heart Slate is combined with the Mystery Part.

Trivia

 * This dungeon was made by Yatterman.
 * This dungeon (as well as the second half, Crystal Castle) was moved from the Winden Forest Relic and placed in the overworld of Winden as its own dungeon.
 * There is a story surrounding the creation of this dungeon as well as the Crystal Castle. It is known as The Story of Winden.
 * Announced only a while before the release of Tanren, Yatterman had mentioned that Crystal Ruins and Crystal Castle would be removed from Winden Forest, and be added to the overworld of Winden as its own dungeon. However, this was pushed back for some time due to personal issues outside of the game. Yatterman vowed to move the two dungeons before the end of December 2012, but it was moved in January 2013 instead.
 * Kabuto was a spawn in this dungeon, however it was removed with the introduction of the Dome Fossil which can now be found there.
 * Regice has multiple Buffs placed on it.
 * Regice, unlike other legendaries, has the rarest chance of dropping a Heart Slate due to how often it appears.