To unlock Celestial Glacier you must reach level 10, which requires 80,000 xp. Earn xp by completing challenges (Gold is worth 750) and caring for your pet when he needs food, water, etc (I believe higher priced food and water gives more xp, such as a steak giving 2250 xp).
This location will also complete the Pirate Map and unlock the Treasure Hunter achievement as well.